ENTOMOLOGICAL CONTRIBUTIONS -NO. IL 



I. ON THE LARVA AND IMAGO OF SESIA DIFFINIS, Harris. 

 By J. A. LINTISrEK. 



The larva of the above Sphinx, nearly mature, was taken in the 

 vicinit}^ of Alban}^, July 4tli, feeding on Diervilla trifida (bush 

 lioneysuckle). Tlie following description represents it at maturity : 



The head is oval, with small whitish points. The body tapers 

 moderately anteriorly, and on the last three segments ; the vascular 

 line is distinct, and of a brownish shade ; the dorsal region is greyish- 

 pink ; the lateral region yellow-brown, deepening into reddish-brown 

 below the stigmata ; the ventral region is brownish-red ; midway 

 between tlie vascular line and the stigmata is a pale yellow line, 

 proceeding from the posterior portion of the collar, and terminating 

 in the horn. The granulations of the collar anteriorly are yellow ; 

 those of the body are white and double-rowed upon the first annulet * 

 of each segment, arranged rectilinearly on the last annulet, and 

 irregularly on the intervening ones. The stigmata are oval, black- 

 bordered, and with a white dot at each end. The legs and prolegs 

 are unicolored with the ventral region. The caudal horn is reddish, 

 straight, acutely granulated, and measures two-tenths of an inch in 

 len2:th. 



* In the Sphingidfe, and in some other familicB of the Lepidoptera, the segments of the larvss are 

 divided by impressed encircling lines into several (usually eight) subequal parts, which, by Clemens 

 and others, have been denominated ivHnkles. In consideration of their constant character and 

 marked features, it would seem proper that they should be known by a name implying less of irreg- 

 ularity and chance, and, regarding them as subdivisions of the primary "rings" of the larva, I 

 have, accordingly, in these notices, designated them as annulets. 



In the Sphinges, the segments four to ten inclusive, or all the stigma-bearing segments, except the 

 two terminal, are divided into eight of these annulets (on segment four the two anterior are not 

 readily detected). The first three annulets encircle the body, forming complete rings ; the impressed 

 lines which define the remaining five become obsolete over the prolegs. The position of the stigma 

 is uniformly between the third and fourth annulets, somewhat encroaching on the latter. In some 

 of the species, the first annulet is subdivided laterally. 



These annulets are a prominent feature in the ornamentation of the larva of Ceratomia quadri- 

 cornis Harr., where each one is crowned with an elongated papilla, forming, in combination, the 

 conspicuous dorsal row of papillae or fleshy serrations which imparts so marked a character to that 

 peculiar larva. 



