190 THE CANADIAN ENTOMOLOGIST. 



explained. Dr. David Sliarp calls attention to Dimmock's hitherto 



accepted statement, and states that Schmidt found the egg-bearers in 



DipIo7iyc]ius were all males. ^ It was an American woman, Miss F, W. 



Slater,* who finally established the fact that the female seized the male 



forcibly and converted him into an animated portable incubator, an 



observation noted by Dr. L. O. Howard in his Insect p]ook, p. 279. I 



have observed the process several times in my aquaria, although not from 



the very beginning. I'iie female places herself on top of the male, her 



thorax extending outward and her legs hooked under him ; now, starting 



somewhere near the middle and sidling along every little while, she works 



her way around him as she fastens her eggs on his back by means of the 



waterproof glue secreted for that purpose. The male all the while hangs 



from the surface, back up, with his legs curled up under him, bravely 



bearing up under his burden. The egg-bearing male, however, like others 



of the same sex, dislikes exceedingly this forced servitude, and does all he 



can to rid himself of his burden. From time to time he passes his third 



pair of legs over the dorsum, apparently in an endeavour to accomplish 



his purpose. In general, however, he keeps to his position at the surface, 



and every now and then moves up and down (|uite rapidly with a peculiar 



springy motion. If he is not able to get rid of it, as sometimes happens, 



he carries his burden till in due time, some ten d.iys or so, all the little 



ones are emerged, when he at last frees him?elf from it. This egg-bearing 



of the male, I imagine, is for the purpose of protecting the ova from the 



voracious appetites of the adults. I have observed males that succeeded 



in casting off the unhatched ova seize them and greedily suck ihe;"n. The 



females, also, are not free from this vice. A peculiar fact in connection 



with the phenomena of oviposition is that copulation takes place while the 



function is being performed, the female interrupting her labours to approach 



the male. 



As development progresses, the ovum swells and lengthens. In 



emerging, the young nymph escapes through a lid at the top of the egg, 



and when all, or at least the greater part, of the ova are empty, the male 



casts off the entire mass of shells, and goes about his business. The 



same female may again burden him, and so far as acpiarium observations 

 go, she deposits several batches of eggs, averaging from 25 to 125'' each, 

 so she may become the mother of a progeny running into the hundreds. 



3. Cambridg^e Natural History, Insects, Part II, p, 566. 



4. American Naturalist, 1899, pp. 931 933. 



5. Dimmock says (1. c.) about 175. 



