Dec, 1916.] Notes on Ceutorhynchus marginatus. 



249 



The Egg. — The egg when laid is pale yellow or nearly transparent 

 and looks like a minute drop of jelly. It is smooth, shining, and 

 without any sculpturing. About a day before hatching the chitinized 

 mandibles of the larva can be seen working beneath the egg shell. 

 The shape of the egg varies somewhat. They are usually elliptical 

 though frequently they tend towards ovoid. Length .6y mm., width 

 .42 mm. 



Larva. — The larva is perhaps the most conspicuous stage of this 

 insect. The adults while abundant are only seen in early spring and 

 even then they are shy and like to hide away at the base of the plant. 

 During May and June one can pick up a dandelion bud most any- 

 where and be quite certain to find two or three fat grubs feeding on 

 the seeds. 



Incubation Period of Ceutorhynchus marginatus. 



The eggs hatch in three to eight days. Although the young larvx 

 take their first meal on the ovules they do not feed very much until 

 the flowers have been fertilized and the seeds have commenced to 

 develop. At this time the larvae feed ravenously, seeming to be aware 

 that they must hasten their growth before the seeds become hard and 

 dried. They burrow into the seeds, eating out the contents and 

 leaving nothing but the seed coats. A single larva requires from 

 fifteen to twenty seeds for its development and when several larvae 

 are present nearly all the seeds of the flower head are eaten. If a 

 dandelion head is opened at this time the presence of the larvae is 

 very evident for great masses of excrement and excavated seeds fill 

 the head (Plate II, fig. 4). 



The mature larva (Plate I, fig. 2) is a footless grub 5^ to 6 mm. 

 long and i>4 mm. wide. It tapers gradually towards both ends and 



