AN ABERRANT LASIUS^FROM] JAPAN. 1 







WILLIAM MORTON WHEELER. 



In a small collection of Japanese ants recently sent me for 

 identification by Professor S. J. Kuwana, of the Imperial Agri- 

 cultural Experiment Station at Nishigahara, near Tokio, I find 

 a single female specimen of such unusual conformation that I at 

 first supposed it to represent an undescribed genus. On closer 

 examination, however, it proves to be a Lasins strikingly different 

 from the females of any of the known species, and suggests two 

 hypotheses for both of which provision will be made in the fol- 

 lowing paragraphs. The specimen may represent either a new 

 species or merely an aberrant female phase of some one of the 

 known Japanese Lasii. The latter supposition will be considered 

 at length in the sequel; the former calls for the following, perhaps 

 merely provisional, taxonomic description: 



Lasius spathepus sp. nov. (Fig. i, A and B.) 



Female (dealated). Length 6 mm. 



Head cordate, slightly broader than long, with notched pos- 

 terior border and rounded, convex posterior corners and sides; 

 convex above; gula concave, with a median longitudinal ridge. 

 Mandibles small, flattened; apparently 5-toothed, with concave 

 external borders. Clypeus depressed, broadly rounded in front, 

 obscurely carinate in the middle. Frontal area obsolescent; 

 frontal groove distinct. Eyes rather large; ocelli small. Antennal 

 scapes broad and compressed, reaching well beyond the posterior 

 corners of the head; funiculi slender, not clavate; all the joints 

 distinctly longer than broad; joints 1-3 more than twice as long 

 as broad ; terminal twice as long as the penultimate joint. Thorax 

 much narrower than the head, fully twice as long as broad ; meso- 

 notum and scutellum flattened above; epinotum short, rounded 

 above, with the declivity abrupt, straight in profile and longer 

 than the base. Petiole with an erect scale, compressed antero- 

 posteriorly and with its upper margin rather sharp and distinctly 

 notched in the middle. Gaster very short, but little longer than 



Contributions from the Entomological Laboratory of the Bussey Institution, 

 Harvard University. No. 22. 



130 



