Insects. 



GRAPE MANUAL. 



Insects. 



59 



young larva; of all insects. Whenever other food fails, 

 they will even devour the helpless pupae of their own 

 kind. 



We select for illustration one of our commonest 

 species of Ladybirds, viz., the Convergent Ladybird 

 (Hippodamia convergens), Fig. 90, a representing the 

 larva, b the pupa, and c the beetle itself. The eggs of 

 Ladybirds greatly resemble in appearance those of the 

 Colorado Potato-beetle : they are orange-yellow, and 

 laid in small groups on the under side of leaves. The 

 larvae are very active and most of them very hand- 

 somely colored, those of the Convergent Ladybird be- 

 ing blue, orange, and black. When full grown, they 

 hang by the tail to the under side of a stalk or leaf and 

 change to chrysalids. The perfect beetle is orange-red 

 marked with black and white, as represented in the 

 figiire. It derives its name from the two convergent 

 lines on the disc of the thorax. The larvae of some of 

 the smaller Ladybirds excrete a cottony matter, and 

 one of them (belonging to the genus Scymnus) has 

 been found to live underground, preying upon the 

 root-inhabiting form of the Grape-phylloxera. 



THRIPS. These are yellow or black insects, hardly 

 visible to the unpracticed eye, but with the aid of a 

 small magnifying glass at once recognizable by their 

 narrow wings, beautifully fringed with long, delicate 

 hair. The larvae resemble in general form their pa- 

 rents, but differ not only in lacking wings, but in being 

 of blood-red color. We refer to the Thrips and figure 

 herewith given (Fig. 91), a black species with white 

 wings (Thrips phylloxeras, Riley), because it is one of 



the most efficient enemies of the Grape-phylloxera, 

 living within the leaf-galls caused by that pest, and 

 doing more than any other species to keep the gall- 

 inhabiting form of the Phylloxera within bounds. 

 According to the recent classification the Thrips form 

 a separate family, Thysanoptera, of the Order Pseudo- 

 neuroptera. 



LACE-WING FLIES. These play a very important 

 rdle in the destruction of injurious insects, but here 

 it is only the larva which does the beneficial work, 

 the imago not being predaceous. These flies may be 

 easily known by their delicate, greenish or yellowish 

 wings, their brilliantly colored eyes; as well as by 

 the peculiar, offensive odor emitted by them. The 

 species represented herewith (Fig. 92) is the Weeping 

 Lace-wing (Chrysopa pluribunda, Fitch), but there are 

 many other species of this and allied genera which form 

 the family Hemerobiidse of the Order Neuroptera. 



Fig. 92. 

 LACE wise FLY: a, eggs; 4, larva; c, cocoon. 



The eggs (Fig. 92, a) are adroitly deposited at the tip 

 of long, silk-like stalks fastened to leaves and twigs. 

 Sometimes these eggs are deposited singly, sometimes 

 as shown in the figure, in little groups. The larvae 

 (Fig. 92, b) are very rapacious and move actively about 

 in search of prey, which consists of soft-bodied insects 

 and eggs of insects. When ready to transform, the 

 larva winds itself up into a wonderfully 'small cocoon 

 (considering the size of the insect which makes it and 

 issues from it), as shown in Fig. 92, c. The imago 

 issues through a neatly cut circular opening of this 

 cocoon, also represented in the figure. 



SYRPHUS- FLIES. Associated with the Lace-wing 

 larvae wefrequently find another class of larvae or mag- 

 gots of quite different appearance. They are blind and 

 without legs, slowly moving about by means of stiff 

 hairs with which they are covered, while others adhere 

 to the leaves by means of a slimy secretion and move 

 by alternately contracting and stretching out their 

 bodies. In coloration these larvae vary greatly, some 

 being dirty- white or brown, while others are green or 

 striped like caterpillars. Their prey is the same as 

 that of the Lace-wing larvae and their work is just as 

 thorough. These are the larvae of a large family of 

 Two-winged flies, called Syrphidas, very numerous in 



Fig. 93. 

 Root-louse SYRPHUS-FLY: a, larva; 6, pupa; c, fly. 



species as well as in individuals. When ready to 

 transform the larva becomes rigid, with the outer skin 

 hardening and forming what is called a puparium, 

 while the real pupa lies within this outer covering. In 

 due time the fly issues from this puparium. The spe- 

 cies figured in the accompanying cut (Fig. 93) is Pipizct 

 radicum, Walsh & Riley), a representing the larva, b 

 the puparium from which the imago has escaped, c the 

 fly itself. This species lives, in the larva state, under- 

 ground feeding both on the Apple-tree Root-louse and 

 on the Grape-root-louse. 



THE INSIDIOUS FLOWER-BUG. This insect, of which 

 we represent herewith a highly magnified figure (Fig. 

 94), is quite commonly met with on all sorts of plants 

 infested by injurious insects ; and anyone who cares to 



