HEMIPTEROUS INSECTS ON ORANGE. 157 



Broods. As in the case of the Leaf-rollers (Tor trie idee), there* are 

 many broods during the year. The moths have been bred in February, 

 March, April, June, July, September, and October, and caterpillars of 

 all ages are found at any time during the summer. In December and 

 January, however, only the pupa is obtainable. 



Remedies. The extent of direct injury done to the Orange by these 

 Web-worms is slight. It is, however, desirable to remove them from 

 the trees, as the tangles of web harbor Scale-insects, and by protecting 

 them from enemies foster their increase. In many cases Scale-insects 

 will be found to have made their appearance; brought there, in all 

 probability, by the spiders. It is therefore a wise plan to cut away 

 the infested portion, usually comprising only a small inside branch. If 

 this cannot be done without too much mutilation as, for example, on 

 young plants after removing the web from the branches they should 

 be sprayed with one of the washes recommended in the treatment of 

 Scale-insects. 



INSECTS OF THE ORDER HEMIPTERA. 

 THE ORANGE APHIS. 



(Siphonophora citrifolii Ashmead.) 

 [Plate XIII, Fig. 3 a, &, c, and d.] 



The history of the common Plant-louse of the greenhouse and gar- 

 den has often been written and, briefly stated, is as follows : In the 

 autumn eggs are deposited singly in sheltered places; from these hatch 

 in the spring only wingless females, which do not lay eggs, but are vi- 

 viparous and produce young without the appearance of males. During 

 the summer one generation follows another with an astonishing rate 

 of increase; each brood consisting solely of wingless agamic females. 

 Finally, the last brood in the fall consists of winged males and females, 

 by whom the winter eggs are produced and the perpetuation of the spe- 

 cies secured in the ordinary manner. 



The Aphis of the Orange (Plate XIII; a, wingless female; 6, winged 

 females) is a dark green Plant-louse, from 1.5 to 2 mm (yf - to - 4 -- - inch) 

 in length, and hardly distinguishable in a popular description from 

 some of the species common everywhere in greenhouses and gardens. 

 It has parti-colored legs and garnet-red eyes. The hue of the body 

 varies with age, from light yellowish-green or rusty green in the very 

 young, to dark green in the adults. The winged individuals are of so 

 dark a green as to have been described as black, and the young of this 

 form are distinguishable at an early age from those destined to remain 

 wingless, both by their darker color and more prominent tubercles 

 upon the upper surface of the body. Two pairs of these prominences 

 gradually develop into wing-pads, and after the final molt become well- 

 formed and transparent wings. 



