358 NEUROPTERA 



notum, of variable form and size, is very distinct in the perfect 

 Insects ; with it are connected the largely developed pleura. The 

 episternum is very peculiar, consisting of an elongate chitinous 

 slip on each side hanging downwards, the two not quite meeting 

 in the middle ; they thus form the margin of the very large 

 anterior orifice, and are in contiguity with the cervical sclerites ; 

 behind them are the very large epimera. The prosternum 

 appears to be usually entirely membranous ; in some cases the 

 sclerite in it is small and delicate, and apparently differs accord- 

 ing to the species. The meso- and meta-thorax are sub-equal 

 in size ; the mesosternum forms a peculiar, large, adpressed fold. 

 The metasternum is membranous, but is terminated behind by 

 a sclerite apparently of variable form. The hind body is volumi- 

 nous, simple in form, consisting of ten segments and bearing at 

 the extremity two short distant cerci of a variable number of 

 joints. The terminal ventral sclerites differ greatly in form 

 according to the species and sometimes according to the sex ; 

 there are sometimes, if not always, present near the extremity 

 two peculiar minute biarticulate styles, called appendices anales. 

 The coxae are all large, free, and exserted ; at the base of each 

 is a transverse trochantin. The femora are articulated with 

 the trochanters, not with the coxae ; both femora and tibiae 

 are slender, the tarsi small, four - jointed ; the terminal joint 

 elongate. 



It is now well established that Termites have a means of 

 communication by sounds. The individuals have a peculiar way 



of jerking themselves, as has 

 been frequently noticed by ob- 

 servers of the Insects ; these con- 

 vulsive movements may possibly 

 be connected with the production 



Fid. 22 /. Front tibia and tarsus of 



Calotermes rugosus larva, showing of SOUnd, which may perhaps be 



auditory organ. x 90. (After F. eyoke d by COIltact between the 

 Muller.) 



back of the head and the pro- 



notum ; the exact mode by which the sounds are produced is not, 

 however, known. The existence of an auditory organ in the 

 front tibia has been demonstrated by Fritz Miiller, 1 and we 

 reproduce (Fig. 227) one of his figures. The structure seems to 



1 Jena. Zeitschr. Naturw. ix. 1875, pi. xii. See also Stokes in Science, xxii. 

 1893, p. 273. 



