ENTOMOLOGY

64 SANITARY ENTOMOLOGYof the insects named will hatch, the larvre within twenty days afteringestion of the eggs developing to the infective stage. In this stage thelarvre are coiled up in cysts in the muscles of the prothorax and legs,differing in location from the larvre of G. scuta tum which in artificiallyinfected cockroaches, as in their normal hosts, dung beetles, are foundencysted in the body cavity •.drduentna strongylina (Rudolphi, 1819) Railliet and Henry, 1911This p.ematode in its adult stage occurs in the stomach of the pig.Seurat (1916) has recorded the presence 'of larval nematodes in thestomach of a pig associated with adults of A. stro'11(Jylina which he considersbelong to this species. He has found morphologically similar larvalnematodes encapsuled in the body cavity of Aplwdius rufus castaneus and·states that they also occur in beetles of the genus Onthophagus. Apparentlyno feeding experiments have been carried out. Presumably thelife history would be similar to that of Gongylonema scutatwm, Protospiruramuns, etc., that is, the eggs of the parasite passed in the feces areswallowed by beetles, the larvre develop in these insects to the infectivestage, and are transferred to the definitive host when the beetles areswallowed by a pig, after which the young worms complete their developmentto maturity. Seurat (1919) records the presence of encysted larvmof .d. strongylina in the stomach wall of the Algerian hedgehog (Erinaceusalgirus). Apparently, therefore, the larvre of this species that occurencysted in insects, like those of Physocephalus se:calatus and Spirocercasan(Juinolenta, if ingested by vertebrates other than the normal hosts ofthe adul"t worms, migrate out of the lumen of the digestive tract andbecome reencysted in the neighboring tissues.Physocephalus sexalatus (Molin, 1860) Diesing, 1861The adults of this nematode live in the stomach of the pig, dromedary,and donkey. Seurat (1913) has found two successive larval stages precedingthe adult in the stomach of the definitive host (donkey) and hasalso (1916) established the common occurrence of the earlier of these twostages in various dung beetles (ScaralJO!us [Ateuchus] sacer, S.[.d teuchetus] variolosus, Geotrupes douei, Onthophagus nebulosU8 andO. bedeli). Pigs of course are commonly known to be coprophagus intheir feeding habits and Seurat states that the donkeys of Algeria, wherehis investigations were made, commonly devour fecal matter swarmingwith dung beetles. The way in which the larvre of P. se.valatus reach theirfinal host is therefore evidently through the ingestion of infested beetlesby pigs, donkeys, or dromedaries. Presumably of course the beetles be-