PLATE VI. 



Common Cockroach {Periplaneta Orientalis), 

 Female, 



Dissected so as to show its digestive, nervous, and reproductive apparatus ; the 

 'fat body,' and a considerable portion of the dorsal integuments having been 

 removed. 



Of the external organs are seen the multi-articulate antennae, 

 the segmented anal appendages or ' cerci/ the compound eyes, por- 

 tions of the epicranium, of the pronotal, mesonotal, and metanotal 

 elements of the thoracic segments, and of the eight dorsal elements 

 of the abdominal segments ; and finally, the three legs articulated 

 to the three thoracic segments on either side, and consisting each 

 of a proximal segment known as the coxa, a second and much 

 smaller segment, distinct in these, though not in the saltatorial 

 Orthoptera, from the coxa, and known as the trochanter ; a third, 

 \h& femur, beset below with spines ; a fourth, the tibia, more richly 

 armed with spines than the femur ; and the fifth, the tarsus itself, 

 which is quinque-articulate. 



a. Antennae consisting of three elongated basal segments, and 



a multi-articulate appendage made up of as many as ninety- 

 two joints. The antennae of Insects correspond to the 

 so-called ' antcnnules' of Crustacea, and they are here made 

 up of large and small joints in similar proportions, see 

 p. Ill, supra. 



b. I, b. 2, I. 3. Tibiae, sub-quadrangular in shape, and beset 



along their two narrower sides with spines. 



c. ' Cerci anales,^ consisting of twelve segments, the terminal 



one conical, the others thickly beset with hairs. As sexual 

 characters may be noted tlie absence of the sub-anal styles 



