223 



tid groups, but besides a few observations on an European Mantis we 

 have no observations on members of the families Locustidce, Mantidw, 

 and Fhasmidce. The differences in the details of embryonic development 

 observed in the Orthoptera hitherto investigated are so great that all 

 students of the subject must look forward with considerable interest to 

 any results accruing from the study of representatives of these four 

 families. In my search for insects' eggs of a convenient size, procura- 

 ble in abundauce, and representing families heretofore unstudied, I 

 happened on one of the Locustidw, the eggs of which meet the require- 

 ments. The species to which I allude is Xipliidium ensiferuni. Scud., a 

 very common insect about the meadows and marshlands of Wisconsin 

 and the adjacent states. 



Unlike other species of the family whose ovipositiou has been de- 

 scribed, Xipliidium endjhnim does not ovij^osit on or in twigs, but be- 

 tween the scales of a Cecidomyid gall, very common on the willows which 

 grow iu the damp situations haunted by the Locustid. Mr. L. O. How- 

 ard, who kindly examined a specimen of the scaly turnip-shaped gall 

 for me, pronounces it to be very probably produced by Gecidomyia salicis- 

 gnaphaloides, Walsh. On September 8 I observed a female iu the act 

 of ovipositiou. She was perched with her head turned toward the apex 

 of the gall, which contained besides the large white Cecidomyid larva 

 iu the center of its base, a number of the smaller orange-red larvae of 

 an iuquiline Cecidomyid between the scale-like leaves. Slowly and 

 sedately she thrust her sword-shaped ovipositor down between the 

 leaves and, after depositing an egg, as slowly withdrew the organ iu 

 order to recommence the same operation after taking a few steps to 

 one side of where she had been at work. She soon observed me and 

 slipped away without completing her task. 



The subopaque, cream-colored egg is elongate oval, 4 to 4.5™'" 

 long and l""" broad through its middle. One of the poles is somewhat 

 more attenuate than the other and there is a faint curvature iu the 

 polar axis which causes one side of the egg to be somewhat more con- 

 vex than the other. The yolk, very similar in constitution to that of 

 other Orthoptera, is pale yellow. It is inclosed by a delicate vitelline 

 membrane and a thicker, opaque and somewhat leathery chorion which 

 suddenly becomes transparent when immersed in alcohol. The eggs 

 are deposited with their long axes parallel to the long axis of the gall 

 and their attenuate poles upward. They are completely concealed by 

 the leaves, the edges of which close over and very efflcieutly protect 

 them. The number of eggs found in a gall varies considerably. Some- 

 times but two or three will be found, more frequently from fifty to one 

 liundred ; in one small gall I counted' one hundred and seventy and I 

 have opened a few galls which contained more. From these facts I 

 conclude that one female frequently deposits her quantum of eggs in 

 several galls, possibly having some means of selecting the best cradles 

 for her offspring and perhaps trying several till she finds one perfectly 



