258 THE AMERICAN MONTHLY [Sep 



eter. If these are broken open the fully formed tick is 

 seen inside. These are better adapted for mounting than 

 the adult insect which has already sucked blood. The 

 spiracles should be noticed, especially the thoracic ones ; 

 also the toothed claws and the tree-like formation be- 

 tween them, answering to the pad on the foot of the 

 hous€-fly. 



Aphis With Young. — The peculiarity in this case is 

 that the winged female in November ought by all rules 

 to be oviparous. The fact of this one being viviparous at 

 that time of year shows how circumstances modify natu- 

 ral habits. The chrysanthemum from which this aphis 

 was taken was in a greenhouse ; had it been in the open 

 air the aphis would have laid eggs — at least, if entomol- 

 ogists are to be believed. In the slide showing the pupal 

 aphis the wings are still seen confined in their cases. Both 

 larval and pupal aphides produce young : a phenomenon 

 known as Poedogenesis. Aphides during the summer are 

 viviparous and produce their young parthenogetically. In 

 the autumn the union of the sexes takes place and the re- 

 sult is, not living young, but eggs. The specieg of ap- 

 hides are very numerous. The aphis which spins the wool 

 on apple trees has no cornicles. Aphides, like Coccidae, 

 are of the order Hemiptera, and sub-order Homoptera, 

 but belong to that division of the sub-order which has 

 two joints on the tarsus (DimeraB). 



Ovipositor of Tipula. — This is a curious organ of the 

 "Daddy-long-legs," but the parts are not arranged on the 

 slide as in nature. There are 250 species of Tipula known. 

 They lay their eggs in the ground or on the surface in 

 batches of 200 or more. The eggs are black. The grub 

 produced from the egf^ is known as the "leather jacket," 

 and is very destructive. This last remark applies to only 

 two of the 250 species. I should very much like to know 

 what those battledore-like objects lying near may be. 



Ovipositor of Tipula. — Had there been only two of 



