TRANSFORMATIONS OF BUFFALO GNATS. 7 



has observed, are limited to this diet. There are only two definite 

 records to the writer's knowledge of Simulium feeding upon any- 

 thing other than the blood of mammals. One is by Hagen (1883). 

 who states that he found Simulium attacking and feeding upon the 

 chrysalids of a butterfly (Pieris) Neophasia menapia Felder. He 

 does not, however, state the exact species which he found so doing, 

 and remarks that it was similar to the New England "black fly." 

 The other record is by H. Pryer, 1 who states that in Japan he found 

 Simulium attacking the larva of a sphingid, Smerinthus planus 

 Walk., and also the imago of Stauropus persimitis Butl. 



A detailed study was made by the writer in the region of Spartan- 

 burg, S. C, of the feeding habits of Simulium venustum, which 

 was found from early spring to late fall engorging within the ears of 

 horses and mules. Though invariably present on these animals, they 

 were seldom found on cattle or on man. The severity of the attacks 

 of this species depend both upon the time of year and the time of 

 day. It is generally believed that the worst attacks occur in early 

 spring and in early fall, and the writer found adults more numerous 

 during the first three weeks of September than they had been since 

 the middle of June. They appear to be most active from 3 p. m. to 

 almost dusk. They are rather easily disturbed while feeding, and 

 unless much distended will struggle violently to disengage them- 

 selves from the long hairs in the interior of the mules' ears. It has 

 been noticed repeatedly that even the well-engorged specimens will 

 retract their beaks and successfully fly away and not fall to the 

 ground and crawl away to die, as has heretofore been claimed by cer- 

 tain writers. The fact that they are so easily disturbed and bite only 

 under certain conditions probably accounts for the failure thus far 

 of all efforts to get them to engorge while in captivity. While con- 

 fined on the human body in a vial they make frantic efforts to escape 

 and after 20 minutes become so exhausted as finally to remain on their 

 backs with scarcely a sign of life. Whether the vial was covered to 

 exclude the light or not, these experiments were unsuccessful at any 

 time of day, both with reared specimens and captured ones. When 

 placed in jars containing cloth saturated with defibrinated cow's 

 blood a few took a small amount of blood into the crop, but there was 

 no distension of the abdomen. 



OVIPOSITION. 



In the method of oviposition the different species of Simulium, 

 whose life history has been studied in detail, show characteristic 

 adaptations according to their habitat, and may be classified arbi- 

 trarily into two distinct groups. Although this grouping applies 

 clearly to conditions in South Carolina, it is possible that exceptions 

 may be found in other regions. 



1 See Bibliography, p. 35. 



