69 



Then there are the hosts of insects which feed on shrubs and forest trees, in 

 which the fruit-grower has no special interest, and on the grasses and herbaceous 

 plants which in themselves are not obnoxious to him. The name of these insects is 

 "Legion." Lastly, there are the many insects predaceous upon these neutral 

 insects, which neither for good nor for harm affect the fruit-grower's special 

 interests. All these we may pass by, and come to the consideration of — 



IV. Insects Indirectly beneficial to Fruit-culture. — Amongst these must be found 

 a place for such as help to keep down encroaching and troublesome weeds that would 

 be an eye-sore to the fruit-grower, and an injury to the orchard and garden. 

 Pyrameis cardui (Linn.) feeds upon the thistle, Vanessa milberti (Godt.) on the 

 nettle, Danais archippus (Fabr.) on the milk-weed. Bach of them in its perfect state 

 is "a thing of beauty," and, therefore, as the poet tells us, "a joy for ever; " and 

 though the judicious fruit-grower may allow no weeds to establish themselves in his 

 own grounds, it will not be an unpleasing reflection for him that these insects, and 

 others of similar habits, are working at the weeds in the grounds of his slack 

 neighbours. 



But more important in their operations than these are the numerous parasitic 

 and predaceous insects that keep down the numbers of the injurious kinds. Asilus 

 (Bstuans (Linn.), and^. sericens (Say), together with many kinds of dragon flies, roam 

 the air in summer time in search of their winged prey. The larvfe of the Syrphians 

 feed on the plant-lice, or in the bodies of living caterpillars, which they ultimately 

 destroy. The Oicindelidse, or Tiger Beetles, and the Carabidse, or Ground Beetles, 

 devour vast numbers of curculio grubs. Sarpalus calignosus (Say) eats the cut-worms. 

 The larvffi of the Fire-fly, Photinus pyralis (Linn.) also feeds upon underground 

 larvae, and will even bite its way into cocoon?". I have found it in the act of cleaning 

 out a cocoon of Kematus erichsonii. The Lady-birds, CoccmeMce, in all their stages, 

 do an immense amount of good in thinning the numbers of the different species of 

 Aphis. The Solitary Wasps and the Sphex-flies are also among the fruit-growers' 

 best insect-friends. Eumenes fraternus (Say) stores its mud cells with paralyzed but 

 living larvse. I once saw Odynerus capra (Sanss.) pounce down upon a colony of 

 full-grown larvse of the imported currant-worm, Nematus ventricosus (Klug). The 

 larvse dropped instanter to the ground ; but the wasp selected its victim, and, with 

 its powerful jaws, nipped it at regular intervals, probably over the ganglia, through- 

 out its length, taking all the twist out of it. It then attempted to fly off with its 

 prey, but found it too heavy. Acting in accordance with the school-boy principle, 

 that "the best pocket for carrying one's lunch is an inside pocket," it nipped off the 

 thoracic segments, and proceeded to make a meal, leaving the head, fore-legs and 

 skin. It then took up the more succulent after-part of the larvas and flew off w ith 

 it, no doubt to add it to the provision it was making for its young. Insects belonging 

 to the various genera of the lehneumonidffi also do yeoman service. Packard tells 

 us that " In Europe over 2,000 species of this family have been described, and it is 

 probable we have an equal number of species in America."* Pimpla pedalis 

 (Cresson) is pai-asitic in the web-worms ; Ichneumon saturalis (Say) in the Army- 

 worm. Gryptus extrematus (Cresson) lays its eggs in considerable numbers in the 

 larvse of Platysamia Gecropia (Linn.) The eggs hatch in the living larvse, and the 

 o-rubs locate themselves in suitable quarters within their hosts. Bach brings the 

 end of its body — where the openings of the two j^rincipal trachse are found — into 

 proximity to one of the stigmata of its host, and so is enabled to breathe. It feeds 

 upon the juices and fatty matter of the unhajjpy caterpillar; and all the food it 

 takes must be assimilated, for its stomach ends in a cul de sac. Think of the 

 condition of the wretched host, with a score or two of grubs sapping its vitals. 

 Surely the most irate, or desponding, fruit-grower, who has been ready to wring his 

 hands, and exclaim with York, in Shakespeare's 2nd part of King Henry V. : — 



" Thus are my blossoms blasted in the bud, 

 And cateriaillars eat my leaves away." 



♦Guide to the Study of Insects, p. 193. 



