smith] the CHRYSOPAS OR GOLDEN EYES 263 



old skin to burst over the thorax. A very clean appearing larva 

 with a clean-cut color pattern emerges and in about an hour the 

 body wall will be hard enough that the larva can walk around and 

 attack ])lant lice. Before the larva is grown, it will molt again four 

 or five days after the first molt. 



A nmnber of very interesting observations and experiments can 

 be made with the larvae. For example, while a nearly grown larva 

 is eating an aphid, the bottle may be turned so that the larva is 

 uppeiTnost, its feet may be then lifted from the glass and the larva 

 forced to hang suspended by the tail. The tail is actually glued to 

 the glass in this case and when the larva walks about, the gela- 

 tinous secretion may be readily seen with the aid of a microscope. 

 If a nearly grown larva be starved a day or two, the food getting 

 instincts and reactions may be studied. It searches everywhere 

 for plant lice with its long jaws and an empty aphid skin is attached 

 just as an aphid would be but it is soon thrown aside. If an aphid 

 be held by a pair of tweezers in front of the larva, it will not see it. 

 If the antennas jaws or any of the body setae be touched, the larva 

 gives evidence at once of having detected its presence. It may 

 grab the aphid before one can get it away. 



Tactile sensations are therefore the most important in food 

 getting. Many other experiments such as using different insects 

 for food, various prepared foods as beef tea, veal syrup, light and 

 dark experiments, forcing a larva to defend itself, placing two 

 hungry lar\^ae together to see the combat and allowing a hungry 

 larva to attempt to puncture your finger may be carried out with 

 interesting results. A Httle patience is required as not all larvae 

 perform just as one would like. 



The spinning of the cocoon when the larva is grown is one of the 

 most interesting things in connection with the study. It requires 

 twent\^-four to forty-eight hours to complete the little oval, white 

 silken cocoon. If a larva has started to spin and is not very far 

 advanced, it may be remoA^ed to a glass slide, a rubber or glass ring 

 placed oA^er it and a cover glass on top so that it is confined for 

 observ^ation under a microscope. In this way the very start of 

 the spinning may be observed. The larva lies on its back and the 

 tail moves rapidly here and there fastening the silken thread around 

 it building first a sort of frame work. The larva shifts at regular 

 intervals so that the cocoon is of uniform thickness. The long 

 setae on the body are broken off with each shift and these go into 



