OBSERVATIONS ON THE LIFE HISTORY OF TAPHROCERUS 



GRACILIS (SAY) l 

 (BEETLE, FAMILY BUPRE3TIDAE) 



Royal N. Chapman 



The bulrush leaf miner, Taphrocerus gracilis (Say) (Say, 1825), belongs 

 to that minority of the family of metallic wood-boring beetles, Buprestidae, 

 which mine in the leaves of plants. The eggs and the larvae have not been 

 described in literature heretofore, and the life history has never been 

 published. So far as is known, this beetle is unique among the Bupresti- 

 dae in that it emerges and feeds for a month or two before it hibernates 

 in the adult stage. 



This species is abundant in the vicinity of the Cornell Biological Field 

 Station, and it was here that the present study was begun under the 

 direction of Dr. James G. Needham. 



DESCRIPTIONS OF STAGES 



The adult beetles 



The adult beetles are shown in Plate II, 3 and 4. They vary in length 

 from 3 to 4.7 millimeters. A large number of specimens from Okefenokee 

 Swamp, Georgia, are uniformly small, measuring only about 3 millimeters 

 in length. Those from central New York and southern Minnesota are 

 in general uniformly large, altho a few specimens have been taken which 

 are nearly as small as those from Georgia. 



The beetles are flattened in form, and the general contour is smooth. 

 They have grooves into which the appendages fit when retracted, and these 

 are so formed that when the legs and the antennae are retracted into 

 them the ventral surface of the body is hardly less smooth of contour 

 than the dorsal surface. The antennae fit into grooves which extend 

 latero-ventrad along the sides of the head and the prothorax. The prc- 

 thoracic legs fold with the tibiae anterior to the femora, while the other legs 

 fold with the tibiae posterior to the femora. The tarsae fit snugly into 

 grooves about the coxae. 



The egg 



The egg of this beetle (Plate I, 1) is oval in outline and measures 0.067 

 by 1.05 millimeters. When first deposited, it appears fluid-like and trans- 

 parent. In a few minutes it becomes whitish, and after the lapse of a 

 few hours it is shiny black. When deposited, it flattens out on the leaf 

 like a drop of viscid fluid with the margins extremely thin and the center 

 about half a millimeter in thickness. Around the margin of the egg there 

 is a transparent substance which adheres so closely to the leaf that some 

 of the epidermis of the leaf is often torn away when the egg is removed. 

 This is evidently a mucilaginous substance secreted by the female to serve 



1 Contribution from the Entomological Laboratory of Cornell University. 



3 



