northeastern part of the cotton belt with that of Victoria, Tex., during the six months from June 1 to November 30, 1902, naturally reveals a considerable range of difference, as does also a comparison of the average temperatures prevailing in those localities during the same period for the preceding eleven years. Wherever it is considered in its effect upon the development of the weevil the temperature given is expressed in degrees of effective temperature-that is, the actual temperature above 43° F. The mean average effective temperature for any month multiplied by the number of days included has been considered as giving the total effective temperature for that month. While this method does not give exactly the correct figures, it will furnish data for a comparison of the various localities, and this study of temperatures will undoubtedly reveal facts which will exert considerable influence upon the status of the weevil in other localities into which it is liable to spread.

The total effective temperature for Victoria, Tex., from June 1 to November 30, 1902, was 6,607° F. For the same period at Dallas, Tex., it was 5,626° F., and at Atlanta, Ga., it was 5,052° F.

The average mean total effective temperatures for the sections of Texas, Louisiana, and Georgia, as given by the Weather Bureau for a series of eleven years, are as follows: Texas, 5,716°; Louisiana, 5,578°; Georgia, 5,234° F.

The effect of this decrease in temperature will doubtless be in some measure counteracted by a certain degree of adaptation thereto on the part of the weevil, but it still seems probable that in the temperature of Georgia a considerable reduction in the number of generations will be found. The emergence from winter quarters will probable be considerably later than the middle of April. The development of progeny will not be as rapid as has been described for Victoria, Tex., in preceding pages. Furthermore, it seems likely that during the warmest periods the life cycle will require from 22 to 28 days. The consequent limited number of generations in a season will be still further curtailed by the earlier period of hibernation, which it seems will begin as early as the latter part of October or the first of November, instead of during December, as was the case during the past two years at Victoria. The date of the killing frosts will, in a general way, fix the end of the active season for the weevil, and this will therefore vary considerably from year to year.

TABLE XXVII.-Temperature comparisons of various cotton sections.

From these considerations of temperature difference and judging the varying influence as ascertained at Victoria, it seems that the weevil may prove less and less destructive as it spreads to the cooler portions of the cotton belt, though this supposition is likely to be nullified by an ability to adapt itself to new conditions.

While it must be admitted that nothing, so far as now known, seems certain to prevent the spread of the weevil to any latitude where cotton is now grown, it does seem probable that its control may be more easily accomplished in the more northern portions of the cotton belt than in the Texas area now infested, and since it has been most positively demonstrated that better than the average crop may here be grown in spite of the depredations of the weevil, there would seem to be no special reason for a panic over the future of the cotton crop. Cotton has been and still will be grown in spite of the weevil. The present promise is that those planters who enter the struggle with determination, and who adopt the advanced methods which have proven successful wherever tried, will realize practically as large a profit from cotton raising in the future as it has been possible to obtain in the past.

DISEASES.

Especially in moist breeding jars, weevils often die from what appears to be a bacterial disease. The body contents liquefy, turning to a dark brown in color, and have a putrid odor. Death follows quickly, though not until after putrefaction has begun. The frequency with which several weevils died in the same jar at about the same time indicates that this disease may be contagious. It has not been found in the fields, however, and may have been due entirely to abnormal laboratory conditions.

It is doubtful whether the following observations upon fungus attacks upon weevils should properly be classed with diseases, but as there is a possibility that the attack may have been of this nature, the observations may be given here.

In July, 1902, a lot of squares sent by mail from Calvert, Tex., to Victoria, was so long delayed upon the road that they were very

moldy when received. Thirteen apparently healthy pupa were removed from these moldy squares with the intention of rearing the adults. The pupa were kept moist, and in a short time 5 died, apparently from the attacks of an unknown species of fungus. The remainder were then kept dry, but in spite of this precaution 6 more died, only 2 becoming adult. In another lot of 27 pupæ, 5 died, apparently from attacks of the same fungus.

Specimens of the dead pupa were sent to the pathologist of the Bureau of Plant Industry of the Department for determination of the fungus. It was pronounced to be a probably new species of Aspergillus. As no species of this genus is known to be parasitic, it may be that the pupæ died from some other cause and that the fungus was entirely saprophytic. The external appearance of the fungus so soon after the death of the pupæ, the large mortality prevailing, and the known fact that pupa develop uninjured in the presence of many species of molds leads to the suspicion that it may have had some part in causing the death of the insects.

In 1894 Prof. C. H. T. Townsend, while engaged in the study of the boll weevil, found in a field at San Juan Allende, Mexico, a specimen of a dead pupa which had been attacked by a species of parasitic fungus (Cordyceps sp.). As no other cases of attack by this fungus have been reported, its occurrence is probably very rare.

PARASITES.

BREEDING OF PARASITES.

Owing to the importance attached to parasites in the control of many pests, considerable time has been devoted to the rearing of parasitic enemies of the boll weevil. From the very nature of the habits of the weevil, no perfectly satisfactory method of breeding these parasites could be devised. The apparatus used was exceedingly simple. Squares which were thought to be infested were picked or gathered in the field, and cleared, so far as was possible, of all that might produce parasites not developed from the weevils. Small lots of these squares were placed in paper bags, each fitting tightly over the open mouth of a glass jar. As both parasites and weevils upon emergence naturally make their way to the light, they could easily be seen in the glass jars and at once removed. Even when thus bred something must be known of the habits of each species of insect produced or of its close allies to determine whether it is really a parasite upon a weevil larva, a hyperparasite, or merely a vegetable feeder developed in the decaying square. Many small flies breed in such decaying matter and were caught in the jars, but these must all be acquitted of being parasites upon the weevil. The results are therefore made somewhat uncertain because of the impossibility of isolating the weevil larvæ. A condensed summary of the results in breeding parasites through two seasons' work is presented in Table XXVIII.

From these observations it appears that 24.4 per cent of the 5,548 squares used produced adult weevils, while only 1.3 per cent of the

FIG. 4.-Bracon mellitor, parasite of boll weevil-much enlarged (original).

total squares contained parasites. Among the parasites obtained, 90 per cent were of the single species Bracon mellitor Say (fig. 4). A single specimen of another undoubtedly primary parasite, Sigalphus curculionis Fitch, was reared. A few specimens of Catolaccus incertus Ashm. may possibly have come from the weevil larvæ, but were more likely hyperpara sites. According to the authority of Dr. William H. Ashmead, of the United States National

Museum, to whom the writer is indebted for the specific determinations and also for information about the usual habits of these parasitic insects, the following species, which were bred from squares, must probably be credited to some other host than the boll weevil: Chalcis coloradensis Cress. and Goniozus platynote Ashm. were probably upon lepidopterous larvæ; Eurytoma sp. and Eupelmus, two spp., usually attack dipterous larvæ in galls and a number of specimens of a species of Ooencyrtus may have been parasitic upon the eggs of some lepidopteron or hemipteron, but certainly could not have reached the eggs of the weevil.

It is very noticeable that the dried squares which were picked from the plants produced by far the largest part of all the parasites obtained, 342 squares giving 50 parasites. In this lot, therefore, 14 per cent of the total number contained parasites of some kind and 13 per cent were undoubtedly developed from the weevil larvæ. Taking all other squares together, 5,286 yielded only 18 primary parasites, or only 0.3 per cent.

Previous efforts to breed parasites of the weevil yielded as meager results as those which have just been recorded, though they add to the number of species. In 1894 Prof. C. II. T. Townsend bred, at Corpus Christi, Tex., a single specimen of Urosigalphus robustus Ashm., which was in all probability a primary parasite, as was also Bracon dorsata Say, of which

Mr. Schwarz obtained two specimens at Goliad, Tex., in the fall of 1895. A specimen of Eurytoma tylodermatis Ashm., also reared by Mr. Townsend, may possibly have had some other host.

ventricosus

Pediculoides Newp. This small mite has been thought by some scientists to be the most promising parasite yet found attacking the weevil. It has been experimented with quite extensively by Prof. A. L. Herrera and his assistants of the Mexican Commission of Parasitology. The mites breed with extreme rapidity, the larvæ of wasps being their usual hosts. Both sexes attain full physical

FIG.5.-Enemy of cotton boll weevil, Pediculoides ventricosus-much enlarged (adapted from Brucker).

and sexual maturity while yet within the body of the mother. The males are exceedingly tiny, as are also the females, when they first leave the mother mite. As the females become gravid, however, their abdomens swell to an astonishing size as compared with the rest of the body, being distended by the rapid growth of the young mites (fig. 5). When these are born the mother dies, while the offspring mate, and then immediately begin the search for food. The idea of the Mexican investigators was that these tiny parasites would be able to enter the square through microscopic orifices in the outer layers, and that they would attack and destroy the weevil larvæ and pupæ within. Upon his return from a trip to Mexico in the fall of 1902, the senior author brought with him, through the kindness of Pro