LEAF-ROLLERS ON ORANGE. 



lf)3 



cZ 



FIG. 72. Trichogramma minuta. 

 Riley.) 



(After 



method young trees can without difficulty be kept free from their 

 attacks. 



PARASITES. Trichogramma pretiosa Eiley. This minute Chalcid 

 fly, well known as the parasite which renders effective aid by destroying 

 the eggs of the Cotton Worm, also infests the egg clusters of the Orange 

 Leaf-roller. The mother parasite deposits a single egg in each cell like 

 egg of the Tortrix, and within this nar- 

 row cell the young parasite finds food 

 and domicile until it has completed all 

 its changes. Then it eats its way out, 

 making a ragged hole in the shell, and 

 emerges as a perfect four- winged fly like 

 its parent. The fly is 0.3 mm (-^ inch) 

 long, clear yellow in color, with ruby 

 eyes and iridescent, hyaline wings, 

 which are delicately fringed with hairs. 

 It has been bred from the Tortrix eggs in March and also in September. 

 Fig. 72 represents Trichogramma minuta, a closely-allied species, which 

 differs from Triclwgramma pretiosa only in color and the form of the 

 small joints of the antenna. 



MiotropisplatynotceHowsir'Ct. 12 A slender hymenopterous fly has been 

 bred from the larva of the Orange Leaf-roller. It is honey-yellow 5 

 head lemon-yellow, with dark eyes and antennae. The head is much 

 wider than long, and bears above three dark-colored, simple eyelets 

 (ocelli). The wings are hyaline. Three or four maggots of the parasite 

 are found living within a single caterpillar of the Tortrix, which is at 

 last almost completely devoured by them. The parasites form naked 

 pupae, loosely disposed within the tubular web of the destroyed Leaf- 

 roller, and in about nine days change to adult flies by casting the thin, 

 transparent skin of the pupa. The flies were obtained in September. 



Polysphincta albipes Oresson. Cocoons of slightly yellowish, coarse 

 silk, loosely spun, were found by Professor Comstockon an orange leaf, 

 at Rock Ledge, Fla. The flies issued in February. They have been 

 described by Mr. Cresson in the Keport of the Commissioner for 1879, 

 p. 208. The body is dull red, smooth and polished 5 head black, with 

 white mandibles; wings hyaline, and legs white. Length 7 mra (f- 

 inch). This insect is somewhat doubtfully considered a parasite of Tor- 

 trix rostrana. 



Goniozus n. sp. ; 13 family Proctotrupidce. A minute parasite is bred 

 from the caterpillar of the Leaf-roller. It has a shining, black body, 

 with yellow legs and antennae, and hyaline wings, with a dark-brown 

 stigmal spot. Length 2.5 mm (^ inch). Four or five of the parasites 

 are found in a single caterpillar. They spin oval cocoons of whitish 

 silk within the tubular web of the Tortrix. The parasites issued Octo- 

 ber 1. 



