100 MISCELLANEOUS PAPERS. 



to be practically the same as those of scutellata. Some of these eggs, 

 taken from a dead and dried female, were placed on pieces of leaf and 

 fed to several species of caterpillars. The excrement of these cater- 

 pillars was carefully examined the next day and many of the eggs 

 found therein, most of them empty, but two from the excrement of an 

 arctian had passed through entire. The bits of leaf that this arctian 

 {Diacrisia virginica Fab.) had' swallowed with the eggs were in many 

 cases six to eight times as large as the ^gg^ conclusively demonstrating 

 that these minute tachinid eggs can be swallowed entire by cater- 

 pillars with their food without injury to the Qgg. The arctian was 

 opened nine days after, and a small pacida maggot, probably in its 

 second stage, was found in the midst of a fat body next the alimentary 

 canal. Thus the first step was gained toward a verification of the 

 existence of this remarkable and hitherto reluctantly credited leaf- 

 ovipositing habit in certain tachinids, including the removal from 

 Sasaki of the stigma under which his startling observations had 

 placed him. 



ZENILLIA LIBATRIX Panzer. 



A second step, which, in our opinion, practically removes all linger- 

 ing doubt of the truth of our conclusions, was taken when ZenilVta 

 libatrix Panz. was studied. This is another summer-issuing, double- 

 brooded species, whose eggs are quite similar in all characters to those 

 of Pales pavida and Blepharipa scutellata. Although our supply of 

 the flies was extremely limited, yet the very few females under ob- 

 servation, while they did not reach the point of actual oviposition, 

 lived long enough to give us a decided insight into their habits. 



We have found that female tachinids, Avhen nearing their oviposit- 

 ing period, will attempt oviposition and simulate with the ovipositor 

 the action of an ovipositing female. In many instances we have 

 observed ovipositing females make repeated attempts, thrusting 

 the ovipositor at the caterpillars several times before actually 

 de]Dositing an egg. The last two of the libatrix females — which, 

 by the way, had manifested the same alarm at the proximity of 

 caterpillars as had the females of P. pavida and B. scutellata — 

 were seen to touch the ovipositor excitedly as many as thirteen 

 successive times to the newly eaten edge of a leaf where cater- 

 l^illars had just been feeding. No egg was deposited, but the action 

 showed the intent and, in our opinion, conclusively indicates the 

 habit. About 150 mature eggs of Z. libatrix were secured from the 

 last two females, after these died, and were fed on pieces of leaf to 

 caterpillars of Euvanessa antiopa L., Melalopha inclusa Hbn., and 

 Schizura concinna S. & A. The result of this experiment remains to 

 be seen, but I hazard the prediction that Z. libatrix^ P. pavida, and 

 B. scutellata will all be found to possess the leaf-ovipositing habit. 



