276 ENTOMOLOGY 



of a plentiful supply of food, obtainable with little or no exertion, and 

 indicate, not primitive simplicity of organization, but a high degree of 

 specialization, as we have said before. The embryonic development of 

 parasitic larvae is frequently highly anomalous, as appears in the chapter 

 on development. 



Maternal Provision: Excepting several families of Hymenoptera 

 and the Termitidae, few insects make any special provision for the wel- 

 fare of the young beyond laying the eggs in some appropriate situation. 

 Many insects, as walking-sticks (Phasmidae) and some butterflies 

 (Argynnis) simply drop their eggs to the ground, leaving the young to 

 shift for themselves. Most insects, however, instinctively lay their 

 eggs in situations where the larva is sure to find its proper food near at 

 hand. Thus various flies and beetles deposit their eggs on decaying 

 animal matter, butterflies and moths are more or less restricted to par- 

 ticular species of plants, and parasitic Hymenoptera to certain species of 

 insects. The beetles of the genus Necrophorus go so far as to bury the 

 body of a bird, mouse or other animal in which the eggs are to be laid; 

 and in this instance the male assists the female in undermining and 

 afterward covering the body. A similar co-operation of the two sexes 

 occurs in the scarabaeid beetles known as " tumblebugs," a pair of which 

 may often be seen rolling along laboriously a ball of dung which is to 

 serve as larval food. The female mole-cricket (Gryllotalpa) is said to 

 care for her eggs and even to feed the young at first. 



Hymenoptera display all degrees of complexity in regard to maternal 

 provision. Tenthredinidae simply lay their eggs on the proper food 

 plants or else insert them into the tissues of the plants. Sphecina make 

 a nest, provision it with food and leave the young to care for themselves. 

 Queen wasps and bumblebees go a step further in feeding the first larvae 

 and carrying them to maturity. Finally, in the honey bee the care of 

 the young is at once relegated by the queen to other individuals of the 

 colony, as is also the case among ants. 



Some of the most elaborate examples of purely maternal provision 

 are found among the digger wasps and the solitary wasps; these in- 

 stances are highly interesting, involving as they do an intricate co-ordi- 

 nation of many reflex^ actions as appears in the discussion of insect 

 behavior. 



Among the Sphecina, or digger wasps, the female makes a nest by 

 burrowing into the ground, by mining into such pithy plants as elder or 

 sumach, or else by plastering bits of mud together. The nest is provi- 

 sioned with insects or spiders which have been stung in such a way as 



