410 



ARTHROrODA 



beetles) in the position of the Utter compound eyes. Of other sense organs 

 ordv the tactile hairs of the sldn are known with certainty, while similar 

 hairs on the antenn.e ami aliout the mouth are supposed to be org;ms of 

 smell and taste, since these seitses are known to be well developed. The 

 lvjnpa)idl origans of the Orthoptera are the only structures wliich can be 



Fig. 440. — \'iscera of m;ile cockroach (Pcrif^Ijiietj or:clllJ^s^ iparllyal'lcr Ilu.xlcy'). 

 I-III , se£;raents of thorax and corrospomiing legs; i-io, abdominal segmcnls; j, anus 

 d;', ventral gangUa; a[>, gastric c;vca; <;/, antenna; W, salivary bladder; !,', sexual opening 

 /;, heart; kr, crop; km. gizzard; /. labial palpus; /;;, stomach (the arrow shows the con 

 nection between ;;; and km), alsc^ maxillan' palpus; nig, male genitalia; ot\ a^so]>hagus 

 o^, brain; r, rectum; .?/>, salivary gland; tg, thoracic ganglia, ttg. infrawsophagea 

 ganglion; ■;■«;, yialpighian tubules. 



with much probaliility connected with hearing. These are tliin drum-like 

 parts of tlie eliitiu, framed in thicker portions (figs. 450, 451), bejiealh 

 wliich is a tracheal ^"esicle, with a nerve ending in a 'crista acustica.' End 

 organs similar to those of the ciistx acustica' occur elsewhere titan in the 

 tympanal organs and are regarded as auditory (^clwrdatonar sense organs). 



— A 



4.^0- Fig. 451. 



Fig. 450. — Siile view of grasshopper. ,^, sjiiracles; t, tvm]ianal organ. 

 Fig. 451. — .\nlcrior tibia of a l.ocuslid willi tympanum. ,'; (from Ilalschek, after 

 Fischer). 



The power of producing sound is widely distributed and often higlily 

 developed, the organs for this purpose varying widelv in character. 

 Slridulallng organs are formed Ity ridges on wiitgs and legs, wliich are 

 rublied against each other or against similar ridges on the bodv. Hum- 

 ming is produced li)' the action of the wings or bv tlie passage of air 



