1918] 



Leaf Eating Crane- Fly 



71 



erally, copulation may continue for two or three hours and 

 even longer. In some cases, the sexes remained in union only a 

 matter of a few minutes. 



Oviposition. — Eggs were first observed on the leaves of 

 Traiitvetteria grandis in the breeding-cages on May 25th when 

 the first female was seen to oviposit. On the following day, a 

 few eggs were found on the leaves in the field at Westholme and 

 on a subsequent visit on May 31, were found to be very 

 numerous. 



Fig. la. Ovipositor: 7 /., seventh tergite; 7 si., seventh sternite; 8 St.. eighth 



stemite; 9 pi., ninth pleurite; spt., spermatheca; b. v., bifurcated valve; p. v., 



plonghshare valve; c. v., cutting valve bearing serrated blade 



(5. b.y and plain blade {p. h.). Camera lucida drawing. X 40. 



In order to understand the behavior of the female Cylin- 

 drotoma in ovipositing, it is necessary that we should recapitulate 

 in brief the 'structure of the ovipositor (See Figure la). It 

 consists of a pair of large double-bladed valves (c. v.), each of 

 which is sparsely clothed with rather elongated, dehcate hairs 

 and more closely invested with short ones. The inner blade 

 {s. h.) in each case is serrated along its upper margin which is 

 distinctly recurved externally. The serrations of the proximal 

 half of the blade are directed anteriorly, those of the distal 

 half being directed posteriorly. On each of these cutting valves, 

 external to the saw-edged blade, is a plain blade {p. b.), the 

 upper margin of which is slightly recurved externally and over- 

 topped by the serrated margin of the inner blade. Both blades 

 have their attachment in the dorsal half of the valve. Dorsal to 



