MONOMORIUM. 95 



queen, and her gaster commenced to swell, though unfortunately 

 she died in the early part of next year, without having laid any 

 eggs. 



It seems fairly certain from these experiments, that when an 

 Anergates female has entered a Tetramorium nest, and has been 

 accepted by the Tetramorium workers the seizing of the antennae 

 of the latter by the female being probably an important factor 

 in this acceptance (Adlerz in his recent book also records this 

 fact 27 ) the latter then kill their own queen, or males and winged 

 females if present, and devote themselves to the rearing of the 

 offspring of the parasite ; but it also seems probable that these 

 acceptances are of rare occurrence, and it should be noted that 

 no Anergates brood has actually been reared in captivity. 



MONOMORIUM Mayr. 



[fj.6vos, single ; fAopiov, part (i.e. the maxillary palpi)]. 



Type : Monomorium minutum Mayr (Mayr, 1855). 



The Genus Monomorium comprises a number of species which 

 are distributed over the whole of the warmer parts of the entire 

 world. Several tropical species have become cosmopolitan, being 

 carried by commerce all over the globe, and inhabiting houses, where 

 they have developed into a serious pest one of these, Monomorium 

 pharaonis, being the only species thoroughly established in Britain. 



^ Head longer than broad, oval, or rectangular ; clypeus large, convex, 

 sub triangular, projecting a little over the base of the mandibles, with two 

 obtuse carinae meeting between the base of the antennae ; mandibles narrow, 

 terminal border armed with three or four sharp teeth ; maxillary palpi one- to 

 two- jointed ; labial palpi two- jointed ; frontal carinae short and parallel ; 

 antennae eleven, or twelve- jointed ; first joint oi funiculus long, the following 

 joints, between the first and the club, short and transverse, club three-jointed 

 as long as the rest of the funiculus, its last joint as long as the two preceding 

 together ; eyes oval, generally small. Thorax long and narrow, rounded and 

 a little broader anteriorly ; suture between the pronotum and mesonotum 

 obsolete, deeply marked between the mesonotum and epinotum ; epinotum 

 unarmed. Petiole cylindrical anteriorly, furnished with a high node pos- 

 teriorly ; post-petiole transverse, its node less high than the petiole ; gaster 

 oval, emarginate in front, with distinct anterior angles. 



$ Head as in the Q. Thorax narrow, higher than broad ; mesonotum long, 

 projecting over the pronotum ; epinotum unarmed. Wings : fore-wings 

 with one cubital cell and no discoidal cell. Size much larger than in the ^. 



<$ Head before ocelli flat and broad ; clypeus broad and convex ; man- 

 dibles strong, dentate ; antennae thirteen- jointed, scape short, not as long 

 as the first three joints of the antennae together, funiculus with apical joints 

 a little broader not forming a distinct club. Thorax high ; mesonotum 

 without Mayrian furrows ; epinotum unarmed. Wings as in the $. 



Original description [Mayr Verb. Zool. Bot. Ver. Wien 5 452 



(1855)] : 



" [twos eines, fj.6ptoi> Glied. 



Arbeiter : Der Kopf ist langer als breit, und breiter als der Thorax. Die 

 Oberkiefer sind massig breit, am Innenrande mit grossen, spitzen Zahnen 



