40 



THE COCKROACH : 



Antenna; Eyes. 



A pair of antennoe spring from the front of the head. In the 

 male of the common Cockroach they are a little longer than 

 the body ; in the female rather shorter. From seventy-five 

 to ninety joints are usually found, and the three basal joints are 

 larger than the rest. Tip to about the thirtieth, the joints are 



d" 



Fig. 18. Base of Antenna of Male (to left) and Female (to right). X 24. 



about twice as wide as long ; from this point they become more 

 elongate. The joints are connected by flexible membranes, and 

 provided with stiff, forward-directed bristles. The ordinary 

 position of the antennae is forwards and outwards. 



Each antenna is attached to a relatively large socket (fig. 15), 

 which lies between the epicranium and clypeus, to the front and 

 inner side of the compound eyes. A flexible membrane unites 

 the antenna to the margin of the socket, from the lower part of 

 which a chitinous pin projects upwards and supports the basal 

 joint. 



It is well known that in many Crustacea two pairs of antennae 

 are developed, the foremost pair (antennules) bearing two com- 

 plete filaments. Some writers have suggested that both pairs 

 may be present in Insects, though not simultaneously, the 

 Crustacean antennule being found in the larva, and the Crus- 

 tacean antenna in the adult. This view was supported by the 



