380 HALF-HOURS AT THE MICROSCOPE. 



of handling Cacti, and know how their spines get into the skin 

 and rankle there, will not, I think, find it difficult to refer the urti- 

 cation of caterpillars' hairs to the same merely mechanical cause. 

 A paper on this subject was published in the Monthly Jourti. 

 Micro. Soc. for October, 1874; but it leaves much to be desired, 

 both in the description and the figures. Some foreign caterpillars 

 sting much worse than any we have — r\o\.2^i\y Bombyx processiofiea, 

 on which, with much of an entertaining description, consult 

 Kucheumeister's Manual of Parasites, Sydenham Soc. Trans. 



Scales from Wing of Clothes-Moth, Tinea vestianella, PI. 

 XXIII., Fig. 6). — It is satisfactory to see this slide for reasons 

 similar to those assigned in the last case. The long hair-like 

 scales fringe the hinder margins of the wings. I believe very 

 little has up to the present time been done towards classifying 

 scales according to their form; referring these forms to their 

 proper places on the wings, etc., and explaining their uses. Here 

 is a wide field open for many workers. The older observers con- 

 tented themselves with figuring as many varieties as possible — an 

 endless task where, amongst tens of thousands, no two occur 

 exactly alike. There are those who have attempted their system- 

 atic study ; some have given it up in despair, failing to find any 

 clue through the labyrinth of forms; others have abandoned it 

 from lack of time, or the funds necessary to its successful pursuit. 

 And yet I think there is a clue, and one which is less difficult to 

 find than is commonly supposed. If the feathers of a bird were 

 plucked, a handful of them taken and thrown down indiscrimin- 

 ately, the keenest observer would be unable to refer each to its 

 proper place ; and again, " No two would be found exactly alike." 

 But by studying the feathers carefully and minutely on the skin, a 

 reasonable approach to accuracy may be gained ; their forms and 

 their uses defined. Bear this in mind as the leading idea required 

 for successful study of Lepidopterous scales, and I am persuaded 

 results far surpassing any yet recorded will be gained. As the 

 result of many careful observations, I am of the belief that (in 

 most of the Lepidoptera at any rate) peculiar scales are present, 

 whereby the species yielding them may be characterised. In the 

 Picridce, and some other genera of Butterflies, the males alone 



