14 OKTIIoI'TKUA OF NOKTI I EASTERN A M HUM 'A. 



of that class, to describe briefly the external parts of a 1 \pical 

 specimen. The beginner may thus the more readily grasp the 

 name and location of the parts nsed in classification, as well as 

 the meaning of- many of the technical terms which, of necessity, 

 have to be used in such a work as this. The Ihree regions of the 

 body, the head, the thorax, and the abdomen, with their append- 

 ages, will therefore be considered in order. 



THE HEAI>. The head of the locust is composed of four or 

 more segments or rings, solidly fused together to form a single 

 cavity or hard box of chitin. known as the c/tin-aiiiiiiii. This con- 

 tains the brain and accessory ganglia, and the mouth cavity. It 

 bears or gives support to the antennae, mouth parts, eyes and 

 ocelli; also internally to the muscles moving the mandibles or 

 jaws. The broad basal portion of the epicranium back of the eyes 

 is known as the vcd/mf. the narrower portion between the eyes. 



the vertex, while the long frontal portion 

 as far down as the prominent transverse 

 suture is the front or face. 



The short plate ( <-,//!. below or in front 

 of the epicranium. is the r/y/;r//.v. P.elow 

 this and hinged to its front edge is a mov- 

 able flap known as the lahriiin \ lltr i or up- 

 per lip, to which are attached a pair of 

 jointed Initial jtal/ti. This forms the roof 



3j \^-"*7* tf or Covering' of the front part of the month. 



Fig. _>. From view of th< within which are the large, black-tipped. 



1 ,11] of a locust. i After . ,., 7 , . , 



Lugger). toothed jaws or mandibles (ma), which 



are so attached to the epicranium as to move only in and out ot- 

 to and from a medi-an line. As lias been shown by "shimmer 

 (Psyche, XXII. K.i the two mandibles in Orthoptera ar<> not 

 alike as is generally supposed, but the left one is sliglnly the 

 larger and projects beyond the right one ventrally when closed. 

 The distal ends of the two mandibles are beveled different ly so rhaf 

 when closed the beveled surfaces are contiguous throughout and 

 do not meet on the median lire but always to the right of it. In- 

 serted on the sides of the he-rl insf behind the mandibles and 

 .irclied over the tongue will also be fo'ind a pair of accessory jaws. 

 ;Le uia.rillac (inac). each of which is composed of three parts, the 

 most important being the jointed ma.riUnri/ /tal/mx. The seg- 

 ments of these palpi are usually five in number and vary in sixe 

 and form in different groups therefore being often nsed in classi- 

 fication. The development and shape of these maxilhe in the lo- 



