Jtisects, 



GRAPE MANUAL. 



Insects. 71 



States more than a hundred species, tlie hirger of 

 which may be readily distinguished by their 

 round, convex form, the upper side being "usually 

 red or i^ink. handsome- 

 l.v variegated by black 

 spots. which greatly vary 

 in number and position; 

 also a few species that 

 are black with red spots, 

 while the numerous 

 smaller species are most- 



8.— Ladyuiku. 



ly of a more uniform dark color." With the ex 

 ception of a few species which constitute the 

 genus Epilachna, and a few allied genera, all 

 Lady-birds are insectivorous, and, considering 

 that many species occur in a hirge number o^ 

 specimens and that the larva) are very voracious, 

 an idea may be formed of the great service per- 

 formed by the Ladybirds in lessening the number 

 of injurious insects. The Ladybird larvic are es- 

 pecially fond of preying on 'the plant-lice, but 

 they also feed extensively on the eggs and young 

 larvie of all insects. Whenever other food fails", 

 they will even devour the helpless pupre of their 

 own kind. 



We select for illustration one of our commonest 

 species of Labybirds, viz. the Convergent Lady- 

 bird {Hippodntnin courcnjens), Fig. 98,'/ represent- 

 ing the larva, b the pupa, and c' the beetle itselL 

 The eggs of Ladybirds greatly resemble in ap- 

 pearance those of the Colorado potato-beetle: 

 they are orange-yellow, and laid in small groups 

 on the under side of leaves. The larv;e are very 

 active and most of them very handsomely col- 

 ored, those of the Convergent Ladybird being 

 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 bee- 

 tle is orange-red marked with black and white, 

 as represented in the figure. It derives its name 

 from the two convergent lines on the disc of the 

 thorax. The larvfe of some of the smaller Lady- 

 birds excrete a cottony matter, and one of them 

 (belonging to the genus Sc>/)nnus) has been found 

 to live underground, preying upon the root- 

 inhabiting form of the Grape-pliylloxera. 



Thrips.— These are yellow or black insects, 

 hardly visible to thu unpracticed eye, but with 

 the aid of a small magnifying glass at once recog- 

 nizable by tiieir narrow wings, beautifully fringed 

 with long, delicate hair. The larv;e resemble in 

 general form their parents, but differ not only in 

 lacking wings, but in being of blood-red color. 

 We refer to the Thrips and figure herewith given 

 (Fig. 99), a black species with white wings 



(Thrips phylluxene, Riley), because it is one of 

 the most efficient enemies of the Grape-phyll- 

 oxera, living within tlie leaf-galls caused by that 



pest, and doing more than any other species to 

 keep the gall-inhabiting form of the Phylloxera 

 within I)ouiids. According to the recent classifi- 

 cation the Thrips forn) a separate family, Tby- 

 sanoptera, of the order Pscndonmroptera. 



Lack-win<j Fliks.— These play a very import- 

 ant role in the destruction of injurious insects, 

 but here it is only the larva which does the bene- 

 ficial work, the imago not being predaceous. 

 These files may be easily known by their delicate, 

 greenish or yellowish wings, their brilliantly col- 

 ored eyes, as well as by the peculiar, offensive 

 odor emitted by them. The species represented 

 herewith (Fig. 100) is the Weeping Lace-wino- 



Fig. 100. 

 Lace-wing Fly: a, eggs; b, larva; c, cocoon. 



(Chri/sopa plnnhnmla, Fitch), but there are many 

 other species of this and allied genera which 

 form the family Hemeroblid:e of the order N^eu- 

 roptera. The eggs (Fig. 100, a) are adroitly de- 

 posited 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 larvre (Fig. 100, b) 

 are very rapacious and move actively about in 

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

 sects and eggs of insects. When ready to trans- 

 form, 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. 100, c. The imago issues through a neatly 

 cut circular opening of this cocoon, also repre- 

 sented in the figure. 



Sykphus-flies.— Associated with the Lace- 

 wing larvae we frequently find another class of 

 larv;e or maggots 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 alter- 

 nately contracting and stretching out their 

 bodies. In coloration these larv;i5 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 larv;e and 



Fig. 101. 

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



their work is just as thorough. These are the 

 larv.x of a large family of two-winged flies, called 

 Siirplddi.e, yavy numerous in species as well as in 



