78 THE CAUSES WHICH PROPAGATE 



an open window ; and, next to the Nocturna, the butterfly-like 

 Geometrina are most frequently so attracted. But light exerts 

 an opposite or repulsive effect over other insect species, agreeably 

 with regard to its paralysing power. A notable instance of this 

 is found in an individual of the same group — the Copper Under- 

 wing. The manoeuvres of this moth, when surprised by the 

 autumnal lantern on the sugared tree, are adverted to by Mr. 

 Stainton in his Manual ; and it is really curious to note how the 

 insect avoids the bulPs-eye of the collector by sidling round the 

 trunk into the shade, and yet continues slyly probing the decoc- 

 tion with lengthened haustellum. 



Passing from light, which has its source in chemical union to 

 that emanating from the sun^s photosphere, diffuse daylight is 

 accompanied with kindred manifestation. Diurnal insects, re- 

 leased in a room, generally make for a window, to flutter 

 against the panes they cannot pass ; but others, on the con- 

 trary, and among them most nocturnal kinds, flee the rays, 

 seeking any obscure shade or crevice which offers partial con- 

 cealment. In the crepuscular Dung Beetles, we may witness 

 the two qualities blended, for when let loose from a box the 

 more active males invariably wing for the light, while 

 the more passive female seeks to avoid it by burrowing. 

 Or should we desire an illustration from the light, sensitive 

 group of Lepidoptera, we may find it in a congener of the 

 Copper llnderwings, the Flat-winged Mouse {Aii/pkip//ra trago- 

 pogonis), which, on being dislodged of a bright September 

 morning from its concealment at the window-sash, leaps fran- 

 tically, like an ^geriid, or Cotton Grass Moth, falls theatrically 

 on its back, and after remaining motionless a few moments, 

 recovers itself, and, " mouse-like,^^ runs hopping backwards and 

 forwards along the shadow of the wainscoting, intuitively seek- 

 ing a dusty crevice to wedge into, a proceeding that invariably 

 abrades the scales from the wing-base, so that specimens are 

 seldom found perfect. But this lueifugal character in insects, 

 with its attendant muscular contractions indicating fear, I have 

 already sufiiciently touched on ; love, on the contrary, I shall 

 notice as being fostered by the calm of darkness and gloom — 

 a phenomenon doubtless ruled by the circulative system. 



The compound kaleidoscope eyes of insects, obsolete in 



