302 INSECTS. 



the Frog-hopping insects and others(see PL XII., figs. 2, 

 8, 4). Among these are some of very singular form, the 

 front joint (prothorax) of the thorax being extraordinarily 

 large, and forming sometimes a huge helmet, sometimes 

 a large strangely-shaped shield covering the whole body. 

 The strangest of these forms are chiefly foreign, but one 

 species common in the New Forest is sufficiently re- 

 markable. In this, Membracis cornuta (see PL XII., 

 figs. 4 and 4 a), the prothorax forms a long, pointed, 

 curved, and keeled process over the back, "while on the 

 shoulder it shoots out into two sharp triangular and 

 prominent horns. 



A small insect in this family sucks the juices of ferns, 

 causing large patches of discoloration. 



In the second section, DIMERA, the wings are always 

 clear,* the antennae sometimes of considerable length. 

 The first family is Psyllidae, which consists of insects 

 very like the Aphida3 in appearance and habit, but 

 differing from them in certain respects. 



Both Psyllidae and Aphidse have three ocelli placed 

 in a triangle, and long, or moderately long, slender 

 antenna3. The wings in both are carried in a shelving 

 roof-like position, and the range of size in the species is 

 about the same. In both families there are species which 

 cover themselves with a woolly secretion. 



The Psyllidae may be distinguished from the Aphidae 

 by their power of leaping, their very large thorax, their 

 short rostrum, and antennae of ten joints. The female 

 has a visible ovipositor ; the male, several small upright 



* The wings of Aleyrodes lose the clearness of their appearance through 

 being covered with a white mealy substance, but the membrane itseli is 

 transparent and not thickened. 



