114 ENTOMOLOGICAL NEWS. [May, 



NOTES ON SOME STRUCTURAL PECULIARITIES OF 

 SANNINOIDEA EXITIOSA Say. 



By JOHN B. SMITH, Sc.D. 



In the course of my economic studies on the peach borer I 

 took occasion to examine a considerable series of specimens for 

 structural peculiarities among the adults. While nothing of any 

 very striking importance was discovered there were a number 

 of interesting facts observed that I considered worthy of being 

 figured, and these appear on Plate VI. First of all the differ- 

 ences in the size and character of the scaly vestiture of the wings 

 and body attract attention. At , is a series of scales drawn by 

 means of the camera lucida to exactly the same scale, and this 

 will give an idea of the enormous range in size as well as in 

 shape. The differences in sculpture are also well marked and 

 while in some cases the longitudinal striations only are noticeable, 

 in others a truly reticulated surface seems to be present. The 

 arrow-shaped tufts at the end of the male abdomen are prominent 

 and well known. It is not so well known that at the base of the 

 last segment in the female there is a brush of hair ordinarily 

 lying close to the body like a pencil, but capable of being ex- 

 panded at the will of the insect. This is shown at /, on the 

 plate. Giving this the usual interpretation we may take it to be 

 a scent organ, or " duftapparat." The virgin female soon after 

 emergence from the pupa fixes herself at rest, elevates the ab- 

 domen, projects the ovipositor with the genital organs directed 

 downward, the tufts expanded and awaits the male. Actual 

 copulation was not observed, the males for some reason or other 

 ignoring the females entirely, in captivity. The antennae show 

 considerable differences between the sexes. In the female the 

 joints are not furnished with tufts of hair on the inner side as is 

 the case in the male, but the joints seem to be thicker and toward 

 the tip have somewhat the appearance of a series of bowls set 

 one into the other. This is shown at b and c on the plate; the 

 corresponding structure of the male being shown at d. At the 

 base of the antenna the differences between the male and female 

 are yet more marked, and yet here the greatest modification is 

 found in the female. At e and f these points are brought out 

 and special attention is called to the occurrence of a sensory fovea 

 marked ^ in the female. This is on the basal segment of the 



