28 OUTLINES OF ENTOMOLOGY. 



sects that have them in charge. The larvse of some of the lower fami- 

 lies in the Order are more independent. The mother insect having^ 

 placed her eggs upon the leaves or in the wood on which her instinct 

 teaches her her young will thrive, the latter are, upon hatching, able 

 to provide for themselves. 



When full grown most of these larvte spin a thin, oblong, silken 

 cocoon, within which, after a short rest, they change to pupre. The 

 pupse are quiescent and of the obtected form, each leg, wing and an- 

 tenna being enclosed in its own sheath, which fits it as neatly as a glove 

 finger fits a finger of the human hand. 



All the members are closely applied to the body and remain immov- 

 able until the time of the second transformation. As a rule, eight or 

 ten days only are passed in the pupa state. Then the membranous 

 covering splits on the top of the thorax, the head, legs and embryo 

 wings are drawn out of their coverings, and the insect gnaws open the 

 end of its cocoon and lifts the covering to its cell — unless the latter 

 is opened for it by one of the mature "worker" insects — and after a pe- 

 riod of hardening and general preparation, varying from an hour or 

 two to one or two days, it lifts itself by its strong new wings and sails 

 away into the sunshine. The Hymenoptera are mostly diurnal insects^ 

 and are seldom seen upon the wing, except during warm, pleasant 

 weather. The primary division of the Order, founded upon peculiari- 

 ties of structure and habit, is into two sections: 



1. Stinging Insects (A c u l e A T A), comprising the Bees, Waspa 

 and Ants. 



3. Piercing Insects (T e R e e R A N T i a), comprising several fami- 

 lies of Parasitic Flies, Gall-flies, Saw-flies and Wood-borers. In the 

 first section the sexes are distinguished by a difference in the number 

 of the joints of the antennse and the abdomen — the antennse of the 

 males having thirteen ^ointB and the abdomen seven apparent segments,, 

 while the ante nnPB of the females have hat twelve jointa and the abdomen 

 only stx distinguishable segments. All the females belonging in this 

 section have the ovipositor (the organ by which the eggs are placed) 

 connected with two poison glands ; and whenever this instrument is 

 used as a tceapon, a minute portion of the acrid fluid is forced into the 

 wound made by iis point and causes a burning and stinging pain. 



This poison is used by certain wasps to paralyze other insects and 

 spiders which they collect and store in cells as food for their young. 

 In this case it does not Ic/ll, but produces in the victims a state of help- 

 less torpor in which they continue until devoured by the wasp larvte. 



