IM \ I I Ml". 



live limits; many HctdOpt the him h l>u- and -<|iia,h biitf. ' 



I he periodical ( i. ,id tin- larva of 



the Colorado potato beetle, ihrer; Lepidoplrra ii-ii,-illy four 01 five, but 

 olten more, as in /si.i istihclln, which im.li | a - many B tni i 

 (lie house lly. M nscti d<n<'*tit . two molts ' three larval 

 anl SUggestfl that cnl| and lack ot" food during hibernal ion in an ' 

 (as / isiihcllti) and partial .starvation in the C8 0&C beetle^, . 



.I numher of molts by preventing growth, the hypodermic cdls 

 meanwhile retaining their activity. 



The appearance of the insect often changes greatly with each molt, 

 particularly in caterpillars, in which the changes of coloration and 

 armature may have some 1 phylogenetic significance, as \\Vi-mann has 

 attempted to show in the case of sphingid larvae. 



Adaptations of Larvae. Larva? exhibit innumerable conformitic- 

 of structure to environment. The greatest variety of adaptive struc- 

 occurs in the most active larvae, such as predaceous forms, ter- 

 n-trial or aquatic. These have well-developed sense organs, excellent 

 rs of locomotion, special protective and aggressive devices, etc. 

 In insects as a whole, the environment of the larva or nymph and that 

 of the adult may be very different, as in the butterfly or the dragon fly. 

 and the larvae are modified in a thousand ways for their own immediate 

 advantage, without any direct reference to the needs of the imago. 



The chief purpose, so to speak, of the larva is to feed and grow, and 

 the largest modifications of the larva depend upon nutrition. Take as 

 one extreme, the legless, headless, fleshy and sluggish maggot, embedded 

 in an abundance of food, and as the other extreme the active and 

 "wide-awake" larva of a carabid beetle, dependent for food upon its 

 own powers of sensation, locomotion, prehension,* etc., and obliged 

 meanwhile to protect or defend itself. Between these extremes come 

 such forms as caterpillars, active to a moderate degree. The great 

 majority of larval characters, indeed, are correlated with food habits, 

 directly or indirectly; directly in the case of the mouth parts, sensory 

 and locomotor organs, and special structures for obtaining special food; 

 indirectly, as in respiratory adaptations and protective structures, 

 these latter being numerous and varied. 



Larvae that live in concealment, as those that burrow in the ground 

 or in plants, have few if any special protective structures; active larva?. 

 as those of Carabidae, have an armor-like integument, but owe their 

 protection from enemies chiefly to their powers of locomotion and their 

 aversion to light (negative phototropisni) ; various aquatic nymphs (Zaitlui. 



