SCHISTOCERCA AMERICANA DRURY 147 



ocular somite and has no appendages. It carries the two facetted 

 eyes and three simple ocelli. The second somite is characterized 

 by the presence of a pair of many-jointed, filiform antennae. 

 The third somite, corresponding to the so-called intercalary 

 segment of the embryo, has no appendages but is sufficiently 

 apparent from its neuromere, the tritocerebrum, which innerves 

 the upper lip or labrum. The fourth somite carries a pair of 

 powerful toothed mandibles. The fifth somite carries a pair of 

 maxillce. From a comparison of the maxillae with appendages of 

 crustaceans we conclude that they are composed of a two-jointed 

 protopodite complicated by the presence of two movable plates 

 used in mastication, which must be regarded as a differentiation 

 of the second joint of the protopodite, and an endopodite devel- 

 oped in the form of a palpus, while the exopodite is completely 

 wanting. The first joint of the protopodite is called by entomol- 

 ogists cardo, the second, stipes; the intermaxillary lobe of the 

 protopodite, lacinia, the outer, galea. The maxillary palpus is 

 five-jointed. The sixth somite carries the under lip or labium, 

 which however must be regarded as a pair of second maxillae 

 fused along their inner edge and slightly modified. The fused 

 first joints of the protopodites are known to entomologists under 

 the name of submentum; the fused second joints under the name 

 of mentum. The two lobes corresponding to the right and left 

 galeae of the first maxillae are called ligulce, while the laciniae are 

 wanting. The labial palpi are four-jointed. Projecting into the 

 mouth cavity from the inner surface of the mentum is a small 

 plate called hypopharynx. 



Except for the presence of the eyes and appendages the 

 somites of the head could not be recognized externally for the 

 reason that the skeleton of the head forms a single capsule or 



chitinous endo-skeleton; oe, oesophagus; v, ventriculus; vm, vm', malpighian 

 tubes; i, intestine; c, colon and rectum; sph, sphincter ani; a, end of rectum; 

 tt, testis; ds, vasa efferentia; vd, vas deferens; vs, vesicula seminalis; glm, 

 mucous gland; de, ductus ejaculatorius; pp, penis; vir, tracheal sacs; tr, 

 tracheal tubes; c, coxa; tr, trochanter; fe, femur; ti, tibia; ta\-tas, tarsus; 

 on, claws; py, pygidium. 



