210 l February, 



thej drank, and lovely blue Hair-streaks {TheclcB). The latterj-wlien 

 they alight, rub their wings together, moving their cui'ious tail-like 

 appendages up and down." 



Being desirous of witnessing, if possible, this biological trait in 

 the ThecJce, I one May gave my attention to the habits of the indigenous 

 T. rubi, in order to ascertain if anything similar was observable in its 

 economy. Nor was I disappointed in this, for on two occasions when 

 an individual was sitting sedately on a bramble-leaf with shut wings, 

 I was rewarded by seeing it lift the hinder wings alternately, and, in a 

 leisurely fashion, rub them backwards and forwards over the fore ones, 

 thus betraying, I conceive, the real movement performed by its exotic 

 congeners ; for, on examination of one of them, T. JStolus, the over- 

 lapping fore- wing has its anal vein decidely denuded beneath, where it 

 is also blackened and indurated, indicating friction. 



Regarding the presence or not of a stridulating organ in connec- 

 tion with this rhythmical action, I may mention that beneath, on the 

 overlap of the fore- wing in various species of the genus, the scales are 

 supplanted by a patch of hair, and just above, the anal vein is bare 

 and raised. This bare raised portion, in T. rubi, I have submitted to 



a microscopical scrutiny, and find it 

 crossed at uniform distances by pro- 

 nounced striae, which indicate internal 



Basal portion of the under-sur- ■,• , ^ • i i • 



face of the anal vein of the fore- diaphragms, and coiistrict the tube into 



wing of Thecla rubi, highly mag- 

 nified, a series of bead-like formations, whose 



surface, in common with that of the other fore-wing veins, is 

 pitted, or bears a row of obsolete tubercles resembling those con- 

 stituting a musical organ in certain Acridiidce. Otherwise, the 

 wing veins of this buttei-fly are not blackened nor indurated to 

 form a lima such as we see occurs in larger species ; and thus, any 

 frictional sound caused by these bead-like constrictions or their 

 tubercles moving over the costal vein of the hind-wing would be slight. 

 If we likewise consider the celerity with which Lepidoptera receive 

 intimation of cause of alarm, and their powers of locomotion, the 

 difficulty of approaching the ear near enough to catch the possible 

 stridor of the smaller kinds when at liberty will be evident ; and it will 

 therefore not appear surprising when I state that I failed to detect a 

 sound accompanying the movement in T. rubi* It would be a matter 

 of much interest if it could be determined whether or not the wing 

 movement is a secondary sexual character. T. rubi, like most of the 

 S,hopalocera, pairs at noon. 

 Calais : January 3rd, 1878. 

 * If a sound be produced, it may be of a pitch too high ft be audible by human ears. — Eds. 



