150 CHAPTER IX 



Equally remarkable is the method of parasitization observed Iw Swezey^^ 

 as followed by another tachinid, ChcBtogcedia monticola, a control agent of 

 the " grass " worms in Hawaii. This fly deposits on the leaves of the plant 

 which forms the caterpillars' food. The eggs thus laid are eaten by the host, 

 and in their passage through its mandibles are cracked, permitting the escape 

 of the maggots, which live in and on the body of the host, and eventually 

 destroy it. 



Swezey also observed that if more than one egg was eaten by a caterpillar 

 neither host nor parasite survived. The instinct of the fly seemed to recog- 

 nise this, since it was observed to deposit but one egg on each leaf. 



In Plate XVI, No. ii, are shown the egg masses of DiatrcBa striatalis ,. 

 the upper masses show freshly laid eggs and their appearance just before 

 the emergence of the caterpillar ; below is indicated on the right their appear- 

 ance when parasitized by the proctotrypid, Ceraphron beneficiens, and on 

 the left when attacked by the chalcid, Chcetosticha nana. The last-named 

 parasite is illustrated in Plate XVI, No. 12, and a highly enlarged view of a 

 parasitized egg mass with the parasite fully developed is shown in No. 13. 

 The very different egg mass of Scirpophaga intacta is shown in No. 14. All 

 of these are after Van Deventer.^^ 



The efficiency of the natural method of control has not passed unchal- 

 lenged, and in particular the work of Koebele, Perkins and their associates 

 in Hawaii has been criticised by Froggatt.^^ He was inclined to attribute 

 the diminution of the hopper to the burning of trash, a practice, however,, 

 that had been in use for many years before the advent of the hopper. In 

 addition, the burning of trash is not advised by Perkins, since the hopper 

 can escape by flight, while its parasites are unable to do so. Froggatt's 

 criticism was hypercriticised by Silvestri,^^ who wrote in the highest terms 

 of the work of Koebele and of Perkins. Since then the control of the beetle 

 borer by its natural enemies has been accomphshed, and this feat reflects 

 equal credit on the entomologists who conceived the plan, on the explorer 

 who executed it, and on the association which had sufficient faith in applied 

 science to finance it. 



The Principal Pests and their Parasites. — The number of insects attacking 

 the cane and their parasites is very great, and the list is continually being 

 added to. Below are catalogued a few of the more important pests and their 

 parasites. 



Moth Borers (not including Castnia licus). — In Java hymenopterous 

 egg parasites, Ceraphron beneficiens and Chcetosticha nana. In British 

 Guiana egg parasites, Chcetosticha sp., Trichogamma minutum, Telenomus 

 sp., and as a larval parasite a tachinid fly, Hypostema sp., a braconid wasp, 

 Iphiaulax sp., and the fungus, Cordyceps harheri. 



Army Worms, Cut Worms, etc. — e.g., Spodopttra mauritia, Cirphis uni- 

 puncta in Hawaii by birds, by tachinid flies as ChcBtogcedia monticola and by 

 an ichneumon Ichmumon koebeli. Lamphygma frugiperda in the West 

 Indies by tachinid flies. All these are larval parasites. 



Root-eating Beetle Larvce. — In Porto Rico, Lachnosterna sp. (May beetles) 

 by a scolid wasp Tiphia inornata, by a tachinid fly Cryptomsrigenia auri- 

 facies, and by the green muscardine fungus Metarrhizium anisoplice. In the 

 West Indies Phytalus smithi by a scolid Tiphia parallela ; Ligyrus rugiceps 

 (hardback) by a scolid Campsomeris dorsata ; Prepodcs vittatus by a scolid 



