INSECT VARIETY. 109 



in an adjoining room through the closed door. Tlie first 

 observation of this fact was made about two years since by 

 Miss M. Ball, who has since frequently verified the original 

 observation. Mr. Ball stated that he had himself heard, on the 

 15th of June instant, this remarkable sound. It is probable 

 the sound is emitted only by the male : it has as yet only been 

 heard in the months of May and June.^^ Lastly I examined 

 a specimen of the Water Boatman, Notonecta glaaca, L., and 

 its melanic variety, Fiorcata, Fab., from a slimy farm pond by 

 the roadside, and here also finding the projecting prothorax if 

 moved over the mesothorax elicited a sharp, high creak, submitted 

 the more rounded surface of the scutum to a high magnifying 

 power, and thought to find the cause either as before in lateral 

 limae, or in an obliquely striated band lying along either side of the 

 central lenticular depression. 



On the other hand, the stridulation of certain terrestrial 

 Hemiptera has been already established, but caution is needed 

 in following uj) the investigation from a tendency in tlie skin of 

 these insects to run to wrinkles where a frietional surface could 

 not be supposed to act. Or again, species have been enrolled as 

 stridulators, and stated to possess limse on the ventral arcs of 

 the abdomen played on by the hind legs, without appended 

 notice of their being seen or heard performing.^ Among our 

 northern Land Bugs [Geocorisidfv), the stridulation of the 

 strongly rostrated species of Reduviidse, as Reduoins personatus, 

 and congeners, or of Coranus suhapteras (Plate IV., Fig. 13), 

 on seizure, by rubbing the extreme point of the rostrum (.s) , in 

 the obliquely striated channel on the presternum ij), has been 

 most ingeniously analysed by Herr Westring and Herr Renter. 

 Reditvius testaceus, rare at Malta, possesses a very marked power 

 of stridulation, and species of the genus Pirates are known 

 to perform in the same fashion. t This music, in conjunction 

 with the repulsive scents emitted by certain groups of the 

 Land Bugs, from pyriform glands between the hind legs, 

 intimates a perception akin to fear. 



Our single native species of Reduvins is best known to hen- 



* The stridulation of the genera Pachijcoris, Scutcllcra, Stretrus, Optomiix, 

 Cocloglossa, Ardocoris, and Fsacata, wants confirmation. 

 t Kirby and Spence, Lettr. XVII., p. 317. 



