874 



THE NATURE BOOK 



To accomplish this the shank 

 is brought up close against 

 the thigh, and a quick fiddling 

 motion imparted to the whole 

 flexed hmb. Its sharp edges, 

 which in some species are 

 beaded, grate on the edge of 

 the wing-cover, and the varia- 

 tion of note in different species 

 is to be accounted for partly 

 by the specific difference of 

 veining in the latter and 

 partly by the structure of 

 what is termed the "ear." 

 This, in the Short - horned 

 Grasshoppers, is situated on 

 the first segment of the ab- 

 domen immediately above 

 the articulation of the hind- 

 leg and in front of the first 

 spiracle. All that is externally 

 visible in the common British 

 species is a more or less oval 

 depression. Within this is a 

 tympanum or drum of tense 

 membrane, which is described by Graber 

 as having on its inner face two pro- 

 cesses connected with a bag of clear 

 fluid. The latter is in turn connected 

 with the " auditory " nerve. That the 

 whole is a sense-organ of some descrip- 

 tion admits of httle doubt, and it is as 

 hkely as not that it may be an organ 

 of hearing. 



It is present in both sexes. If, there- 

 fore, we may assume that it affords a 

 means whereby the female shall hear 

 the male, we may also assume that it 

 affords a means whereby the male shall 

 hear the female. 



I have never traced stridulation to 

 a female Short-horn, but I know of no 

 reascm why she should not stridulate. 

 Considering the complications which 

 would arise if both male and female 

 Grasshoppers sang one and the same 

 tune ; considering, too, the possibihty of 

 sympathetic tones (" resonators ") hnking 

 the two sexes together — it is hkely enough 

 that female stridulations are not only 

 invisible to human eyes but also inaudible 

 to human ears. Many people are in- 

 capable of hearing even the male Grass- 

 hopper, though to others the shriUness 

 of his song is almc^st painful. Forty 

 thousand vibrations per second (the top 



SHORT-HORNED FIELD 

 GRAS SHOPPERS 



(S. VIRIUULUS). 



note of the pianoforte gives 

 perhaps four thousand) is con- 

 sidered to be the hmit of 

 human audition. 



In the case of one pecuhar 

 genus of Short-horned Grass- 

 hoppers, known as Tettix, 

 stridulation, if it is accom- 

 phshed at all, must be 

 accomplished by a different 

 mechanism. Tettix is unique 

 in several respects. To begin 

 with, he is honoured with 

 one of the few pure Greek 

 words used in scientific 

 nomenclature, though it is 

 doubtful whether the golden 

 "tettiges," which, according 

 to tradition, the Athenians 

 wore in their hair to signify 

 that they were autochtho- 

 nous, were modelled on 

 Grasshoppers or Cicadas. 

 Both may be said, in a 

 sense, to spring from the soil, 

 for both deposit their eggs below the 

 surface. As a modern name for a genus 

 of Grasshoppers, Tettix appears to have 

 been first employed by the great French 

 entomologist Latreille, and his country- 

 men — it would be difficult to over- 

 estimate the debt of entomology to 

 French genius — appear to have vied 

 with one another in naming the various 

 species after devils. We find, for in- 

 stance, in the old books Tettix Lucifer, 

 Tettix Beelzebub, Tettix Belphegor, and 

 Tettix Asmodceus. The reason for this 

 nomenclature is not, as might be sup- 

 posed, the preference of Tettix alive for 

 warm surroundings, but the blackening 

 and shrivelling of Tettix dead. The 

 suggestive appearance of the cabinet 

 Tettix may be seen in the iUustration. 



The hving Tettix can be easily recog- 

 nised by his small size, his sturdy build, 

 and the lozenge-shaped appearance of 

 his back, which is due to a hindward 

 prolongation of the pronotum. We have 

 two British species — Tettix bipiindatiis, 

 who has a roof-shaped pronotum and 

 short wings, is extremely common; while 

 Tettix siibiilutiis, a more slender but 

 equally short insect with a long, nearly 

 flat pronotum and large wings, appears to 

 be somewhat local. 



