210 Fiftieth Report on the State Museum 



are the red-tailed Tachina-fly, Winthemia ^-pjistulata (Fabr.), formerly 

 known as Nevwnxa leucauice (Kirk.), but which has recently been found 

 identical with this European species; and the yellow-tailed Tachina-fly, 

 which was described as Exorista flavicauda by Riley, but it has recently 

 been pronounced identical with Btlvoisia iniifasciata Desv., by Mr. 

 Coquillett. These two flies are frequently seen in numbers in fields 

 where the army-worm is numerous. They are often so abundant that 

 their buzzing reminds one of a swarm of bees. Their conspicuous white 

 eggs are usually deposited on the head or thoracic segments of the cater- 

 pillar, where they can not be reached by the jaws of the victim for their 

 removal; occasionally they may be found on the anterior abdominal 

 segments. As many as eighteen eggs have been counted on a single 

 caterpillar, but the average is about five. The eggs soon hatch and the 

 young maggots make their way into the body of their host, where they 

 revel in its juices and eventually cause its death. This Tachina oviposi- 

 tion is not, however, necessarily fatal to the larvae, for if it occurs at near 

 the moiling, the eggs may be cast with the skin before the time for their 

 hatching. The proportion of caterpillars parasitized in the vicinity of 

 Albany, was observed to be quite small, probably about 8 per cent., but 

 in the central and western portions of the State, the eggs of these 

 parasites were comparatively abundant. 



The following flies have been reared from the army-worm : Cisiogaster 

 immaailata Mcq., Ocyptera euchenor Wlk., Afi/togra/iuna argenlifrofis 

 Twns., Myophasia ceiiea Wied., Sarcophaga helicis Twns., Sarcophaga 

 cedipodinis Twns., Sarcophaga (two species), Lucilia ccesar (Linn.). It is 

 more than probable that some of these are not true parasites. 



Next in importance perhaps to the Tachina flies as parasites, are the 

 minute four-winged Microgasters, several species of which are parasitic 

 on the army-worm. The most abundant of these is the military Micro- 

 gaster, Apanteles 7niUtans (Walsh), which is usually present, wherever the 

 army-worm abounds. From sixty-two to ninety-six of its larvae have 

 been found in the body of one caterpillar. Its whitish cocoons are often 

 attached to the grass, or to the under side of sticks, stones, etc., in small 

 masses surrounded by more or less loose silk, /ipanteles limenitidis (Riley) 

 is another species parasitic on the army-worm. Unfortunately, these 

 two beneficial insects are in turn parasitized by a Chalcid, Glyphe 

 viridascens Walsh, and by a small Ichneumonid, Afesochorus vitreus 

 Walsh. Haltichella perpulchra (Walsh), is also a parasite of one of the 

 Microgasters above-named. Another smaller parasite of the army-worm 

 is the wingless Pezotnachus minimus Walsh, which in turn has its Chalcid 



