XIFE-HISTOET OF A MO>'^OPnLEBUS. 147 



Dervure. Halteres with five stout hooked bristles at extremity. 

 Antennsp lO-jointed : 3rd-9th each with three nodes, 10th with 

 four nodes ; each node with a whorl of long hairs. Eyes large, 

 compound ; a single ocellus on the dorsal surface at inner 

 margin of each eye. Abdomen with three elongate fleshy hairy 

 procet'ses on each side ; the first shortest, the third longest. 

 Genital sheath not projecting beyond the posterior margin of 

 abdomen : penis usually partially everted, densely clothed with 

 short reversed hairs. Length 5 mm. Expanse 11*50 mm." 



' A noteworthy characteristic of the female is the great difference 

 in size of the individuals, and it would appear that it becomes 

 sexually mature before reaching its full dimensions. 



Egg (PI. 16. fig. 1) : small, dry, shining, oval-elliptical. Colour 

 pink : length 1 mm. 



When they first appear the minute scales are to be found on 

 the under surface of the Sal-leaves, and very shortly after 

 hatching they cluster round the mid and other ribs of the leaf, 

 either on the upper or under surface, but moi^e usually oa the 

 latter, their probosces being buried in the tissues of the rib. 

 When they have somewhat increased in size, and after losing 

 the white hair with which they commence life, they confine 

 themselves to the mid-rib alone, and then undergo a first moult. 

 Erom the first the coccids exude a sticky sugary liquid which 

 coats the leaves, and the little white papery skins of this first 

 moult remain stuck .by means of this to the leaves, and thus 

 serve to attract the eye to the presence of the insect. The 

 female larva appears to spend from 6 to 8 weeks feeding in this 

 way upon the leaves. The scale is not stationary, but moves 

 about over the leaf and from leaf to leaf. It almost certainly 

 gets spread by the agency of other insects and spiders, and 

 probably also by birds. The sticky exudation doubtless greatly 

 facilitates this dispersion, since animals crawling over or fluttering 

 amongst the leaves and twigs of badly infested trees would 

 unavoidably take up to a certain extent portions of it, and with it 

 a few of the young scales. The habit which this insect possesses, 

 in common with most scale-insects, of crawling over every obstacle 

 in its path, even over its predaceous enemies, which it seems 

 quite unable to recognize, doubtless also helps in its diff"usion. 



After from 6 to 8 weeks spent upon the leaves, the period 

 depending upon the favourableness or otherwise of the season, 

 the young scale descends to the twigs, and during the rest of its 



