474 



COMPARATIVE ANATOMY 



CHAP. 



and the tympanum lies the terminal nerve apparatus, the so-called "Miiller's" gan- 

 glion with the scolopophores, whose terminal tubes attach themselves by peculiar inner 

 processes to the middle of the tympanum. The tympanum can be stretched by special 

 muscles. In the Gryllidce and Locustidce the terminal tubes of the scolopophores are 



FIG. 334. Side view of Acridium tartaricum. sj, Stigma of the mesothorax ; s 2 , stigma of the 

 metathorax ; sa, stigmata of the abdomen ; t, drum of the tympanal auditory organ (after Fischer). 



not attached to the tympanum itself, but above it to the integument. The Locustidce 

 possess, besides the Miiller's ganglion with its scolopophores, another series of some- 

 what different scolopophores, lying on a hollow 

 formed by the trachea, which acts as a resonator. 

 The tympanal auditory organs of the Saltatoria 

 lie either (Acridiidce, Fig. 334) in a single pair 

 at the sides of the first abdominal segment, or 

 (Gryllidce, Locustidce, Fig. 333) on the tibiae of the 

 fore-legs. In the last case there are generally on 

 each tibia 2 tympana lying opposite one another. 

 Between the basal portions of the maxillse of 

 Scutigera there lies on each side a pouch, from 

 the base of which small closely -packed plates and 

 hairs rise into the cavity. These plates and hairs 

 stand on equally closely arranged folds of the 

 cuticle. It has been conjectured that these forma- 

 tions, which need further examination, may prove 

 to be auditory organs. 



FIG. 335. Sensory organs con- 

 sidered to be olfactory at the end 

 of the Antennae of lulus Sabulosus, 

 longitudinal section through the an- 

 tenna, k, Sensory cones ; z, sensory 

 points; gk, ganglia of the sensory 

 cones ; gz, ganglia of the sensory 

 points; n, nerve; grz, large cells in 

 the ganglia of the sensory cone (after 

 v. Rath). 



C. Olfactory Organs Gustatory Organs. 



The seat of the sense of smell is, as in 

 the Crustacea, to be sought in the antennae 

 (and perhaps in the maxillar palps as well). 

 The antennae are in the Insecta very 

 often more strongly developed in the 

 males than in the females. The olfactory 

 organs are short processes in the shape of 

 knobs or cones, and generally open at 

 the point; they are found either free 

 or at the base of pits in the antennae. 



