lliird Stage of Insects. 79 



my breeding cases would consume. The skin or crust of 

 insects is unyielding, hence growth requires that it shall be 

 cast. This shedding of the skin is called molting. Most 

 insects molt from four to six times. That bees molt was 

 even known to Swammerdam. Vogel speaks of the thick- 

 ening of the cells because of these cast skins. Dr. Pack- 

 ard observed many years since, that in the thin skinned 

 larvjE, such as those of bees, wasps, and gall-flies, the 

 molts are not apparent; as these larvae increase in size, they 

 outgrow the old skin which comes off in shreds. The 

 length of time which insects remain as larvae is very vari- 

 able. The maggot revels in decaying meat but two or 

 three days; the larval bee eats its rich pabulum for nearly 

 a week ; the apple-tree borer gnaws away for three yeai's ; 

 while the seventeen-year cicada remains a larva for more 

 than sixteen years, groping in darkness and feeding on 

 roots, only to come forth for a few days of hilarity., sun- 

 shine, and courtship. Surely, here is patience exceeding 

 even that of Swammerdam. The name larva, meaning 

 masked, was given to this stage by Linnaeus, as the mature 

 form of the insect is hidden, and cannot be even divined by 

 the unlearned. 



THE PUPA OF INSECTS. 



In this stage the insect is in profound repose, as if rest- 

 ing after its meal, the better to enjoy its active, sportive 

 days — the joyous honey moon — soon to come. At this time 

 the insect may look like a seed, as in the coarctate pupa of 

 diptera, so familiar in the " flax-seed " state of the Hessian- 

 fly, or in the pupa of the cheese-maggot, or the meat-fly. 

 The form of the adult insect is very obscurely shown in 

 butterfly pupae, called, because of their golden spots, chrys- 

 alids, and in the pupa3 of moths. Other pupte, as in the 

 case of beeti (Fig. 34, g') and beetles, look not unlike the 

 mature insect with its antennae, legs, and wings closely 

 bopnd to the body by a thin membrane, hence the name 

 pupa which Linne gave — referring to this condition — as 

 the insect looks as if wrapped in swaddling clothes, the old 

 cruel wa}' of torturing the infant, as if it needed holding 

 together, Aristotle called pupae " nymphs " — a name still 



