JUNE. 197 



molest man in the open clearing in this country, except in 

 one instance ; in which one of the little Clouded Whameflies 

 (Chrysops Sepulchralis? ) suddenly darted at the hand of 

 my brother three successive times without alighting, inflict- 

 ing a wound each time : it left hard whitish lumps, attended 

 by severe pain. The mouth of these insects is a fine piece 

 of mechanism : a fleshy case contains two spiny serrated 

 needles, and two broad lancets, shaped like a knife, working 

 laterally ; these are to cut and enlarge the wound, and in- 

 crease the flow of blood ; within these is a fine tube enclosed 

 in a separate sheath, through which the blood, probably di- 

 luted by some injected fluid (which causes the inflammation 

 and pain) is sucked into the stomach. The palpi are short, 

 straight, and fleshy, and being situated one on each side of 

 the proboscis, guide and guard it from injury while piercing 

 an animal. The whole apparatus, being little larger than the 

 point of a pin, is well worthy of regard and admiration. I 

 have taken the larger species from my horses, so full of blood, 

 that the abdomen was swollen almost to bursting, and of a 

 deep red colour. It appears that on such occasions, as well 

 as in musquitoes, ticks, &c. the vessels and intestines must 

 be either disruptured, the blood flowing among the whole 

 viscera, or else capable of such enormous distension, as almost 

 to fill the whole body. That the bodies of some insects are 

 capable of very great enlargement, is proved by the Chigoe 

 of the West Indies ( Pulex Penetrans), the White Ant of 

 Africa (Termes Fatale), and many species of tick. I have 

 myself often seen in the Southern States, Ticks (Acarus 

 Americanus) which, in their natural state, were not more 

 than one eighth of an inch in diameter, and no thicker than 

 writing-paper, swollen to the diameter of half an inch, and 

 the thickness of an eighth of an inch, merely by the blood 

 sucked from the body of some animal. 



C. The Golden-eyed Pearl-fly (Hemerolius Perla) is 



