2 PROCEEDINGS OF THE NATIONAL MUSEUM vol.80 



THE GENERA OF TROMBICULINAE 



The writer gave a synopsis of the genera of the subfamily Trom- 

 biculinae in his Manual of External Parasites, published in June, 

 1929. Here it is intended to revise and extend that synopsis. Just 

 how many of the genera of Trombidiidae, based upon larval char- 

 acters, should be placed in the Trombiculinae is not known. Un- 

 doubtedly some of the unattached larvae that have been described 

 have hosts that are vertebrates. Also it has been shown that verte- 

 brate-infesting larvae may accidentally be resting on an invertebrate 

 host or possibly some of them may have invertebrates as unnatural 

 hosts. 



KETSr TO THE GENERA OF THE SUBFAMH-Y TROMBICULINAE, TASEn ON LARVA1> 



CHARACTERS 



1. Dorsal plate bearing six setae, exclusive of the pseudostigraaiic 



organs 2. 



Dorsal plate bearing less than six setae, exclusive of the pseudo- 



stigmatic organs 4. 



2. Four of the six setae, borne by dorsal plate, situated along its 



anterior margin ; dorsal plate broader than long 3. 



Only two of the six setae, borne by dorsal plate, situated along 

 its anterior margin; dorsal plate mucli longer than broad; 

 head of pseudostigmatic organs spindle-shaped Schbngastiella Hirst. 



3. Dorsal plate with a median, anterior, knoblike process, but with- 



out crista Leeuwenhoekia Oudeu>ans. 



Dorsal plate without anterior process, but frequently with a 

 crista Hannemania Oudemaus. 



4. Dorsal plate with five setae, exclusive of the pseudostigmatic 



organs ; antero-median seta present ; pseudostigmatic organs 



setiform, flagelliform, clavate, or capitate 5. 



Dorsal plate with only four setae, exclusive of the pseudostig- 

 matic organs; antero-median seta lacking; pseudostigmatic 

 organs clavate Walchia, new genus. 



5. Pseudostigmatic organs strongly clavate or capitate G. 



Pseudostigmatic organs setiform or flagelliform and frequently 



with barbs 7. 



6. Chelicerae armed with a row of teeth above; palpal claw usually 



bifurcate Schongastia Oudemans. 



Chelicerae each with not more than one dorsal tooth; palpal 



claw trifurcate Neoschbng'astia Ewing. 



7. Each chelicera with a row of teeth above; ventral tooth may be 



lacking 8. 



Each chelicera never with more than a single dorsal tooth ; ven- 

 tral tooth always present Trombicula Berlese, 



8. Several subequal dorsal teeth present on each chelicera ; dorsal 



plate well developed ; antero-median seta pectinate. Not endo- 



parasitic in habits Odontacarus Ewing. 



Three unequal dorsal teeth on each chelicera ; dorsal plate ves- 

 tigial or lacking; antero-median seta simple. Living under 

 the surface of the skin of amphibians Endotrom^bicula, new genus. 



