14 NEW YORK STATE MUSEUM 



entomologist who seeks some method of controlling injurious species. A 

 knowledge of the life history and habits of an insect pest is almost essential 

 to a person attempting to control it, because there is usually some weak 

 point in its life history which may be taken advantage of in devising a 

 practical method of keeping it in check. The habits of insects are con- 

 sequently of great practical importance. 



Egg. All insects develop from eggs which present widely variable forms 

 in different species and are frequently of exceedingly beautiful design. 

 They may be placed in clusters, bunches or singly ; on or in leaves, bark, 

 food products, etc.; tucked in all manner of crevices, dropped at random in 

 the grass, or buried in the soil. They may be arranged in single or double 

 rows, placed in bands about a twig, left unprotected or covered with hairs 

 or scales or sheltered by a gummy secretion. A great many eggs are 

 nearly smooth and globular, but those of many butterflies and some moths 

 are somewhat elongated, delicately ribbed and with the' surface broken into 

 innumerable smaller areas by minor ridges. The eggs of a number of true 

 bugs are nearly barrel-shaped and are crowned with a ring of small spines. 

 Certain minute fruit flies (Drosophila) deposit theirs in decaying fruit and 

 were it not for the curious appendages extending on the surface of the 

 semiliquid nidus, the embryo would probably suffocate for want of air. 

 The lace-winged fly(Chrysopa) is of interest because of her peculiar stalked 

 eggs [pi. 20, fig. 18/^] placed in clusters on leaf or twig This curious 

 arrangement is believed to be for the purpose of preventing earlier hatching 

 individuals from devouring their undeveloped relatives. The eggs of a 

 Californian red spider, T e t r a n y c h u s m y t i 1 a s p i d i s, are remarkable ' 

 for the umbrella handlelike stem projecting in the air, from the tip of which 

 strands of silk radiate and are attached at a little distance to the supporting 

 surface. This device probably affords more security on account of the 

 elastic fastening. Many insect eggs are deposited in masses and their form 

 is frequently modified by the supporting surface or surrounding eggs. 

 Some species, like the tussock moth and the tent caterpillar, protect their 



• 1902 Woodworth, C. W. Cal. Agric. E.\p. Sta. Bill. 145, p. 5. 



