234 HEMIPTERA. 



the haulm, between the sheathing leaves, and off the develop- 

 ing grain, and is especially noticeable in the furrow of the wheat 

 seed. They cause the grain to shrivel up, and often produce a 

 white sickly appearance, similar to a disease caused by them in 

 grass in Canada. Another species, T. ochraeeus, is frequently 

 most harmful to melons, cucumbers, tomatoes, &c., under glass. 

 The potato is attacked by T. minutissima (fig. 118, 6 and 8), 

 but it seldom does much harm : the yellow larva has black eyes 

 in this species, the pupae are also of the same colour; the adult 

 is pale-brown, with almost white wings, and is only J of a 

 line in length. The Thrips hibernate at the roots of grass 

 and amongst rubbish, and come forth in spring, when they 

 commence to lay their eggs. Ifumbers of generations are pro- 

 duced in the year. The eggs are very small white bodies, 

 cylindrical, and rounded at one end. 



Prevention and Remedies. — After an attack of Com Thrips 

 the stubble should be burnt, and the grass at the headlands and 

 hedgerows cleared and burnt in the late autumn. In green- 

 houses frequent syringing with clean water keeps this pest in 

 hand. In bad attacks the plants are best sprayed or dipped in 

 a mixture of an ounce of white hellebore mixed in a gallon 

 of water, then boiled and allowed to cool. Fumigation with 

 tobacco is another excellent remedy. 



HEMIPTERA. 



Bugs, Plant-lice, Scale Insects, Etc. 



The Hemiptera are the Bugs, Plant -lice. Scale Insects, 

 Cicadas, and Lice (Pediculi), &c. The characteristics of the 

 Hemiptera are chiefly found in the mouth and the wings. The 

 mouth parts of all the Hemiptera are adapted for piercing and 

 sucking. The mouth is formed of a jointed rostrum made up 

 of an elongated labium, which forms a jointed sheath for the 

 lancet-shaped mandibles and maxUlse (fig. 119). It is by means 

 of this piercing suctorial mouth that the Bugs and Plant-lice 



