MACKODACTYLUS.— ISONYCHUS. 147 



example captured by Buckley in Ecuador, except that the femora and tibise and tarsal 

 joints are tipped with black. 



26. Macrodactylus — — ? 



Hah. Panama, Volcan de Chiriqui {Champion). 

 Also a single example ( 6 ), evidently immature. 



27. Macrodactylus virens. (Tab. IX. fig. 8.) 



Angustus, saturate viridis vel cyaneus, fere glaber, sericeo-subopacus ; antennis piceo-rufis, clava et pedibus 

 nigris ; clypeo valde elongato, antice angustato, apice recurvo-rotundato ; corpore toto pilis sejunctis 

 recumbentibus cinereis vestito ; tborace mediocriter angulatim dilatato. 

 3 . Prosterni spina postcoxali mediocre, apice obtuso ; ventris setis parcissimis, nigris, utrinque 1 vel 2. 



Long. 9 millim. 



Hal. Mexico (Salle, ex coll. Sturm), Zapotlan in Colima [Hbge). 



I have adopted from the Salle collection Sturm's MS. name for this species. 



28. Macrodactylus murinus. (Tab. IX. fig. 9.) 



M. virenti proxime affinis ; clypeo sirnilariter angustato et apice reflexo ; sed differt colore plumb eo-viridi, toto 



dense cinereo adpresso-pilosus. 

 Long. 9 millim. 



Forma typica : M. murinus (Duges, MS.). Pedes nigri. 

 Var. M. subviridis (Duges, MS.). Pedes nigri, femoribus tibiisque basi runs. 



Hab. Mexico, Tupataro, Silao (Salle), Tonila in Colima (Hoge). 



Intermediate states in the colour of the legs are shown in the Salle collection, and 

 both forms occur at Tonila. 



ISONYCHUS. 



Isonychus, Mannerheim, Mem. Soc. Nat. Moscou, vii. p. 69 (1829) ; Burmeister, Handb. der Ent. 

 iv. 2, p. 42 (1855) ; Lacordaire, Gen. Col. iii. p. 247 (1856). 



An exclusively American genus, like Macrodactylus, but apparently restricted to the 

 tropical zone of the continent. Upwards of sixty species have been described, but as 

 little attention has been paid to the extraordinary variation in the colours and markings 

 which the species present, it is probable that many of them are not valid. 



Burmeister says expressly that the legs offer no sexual differences, and other authors 

 have failed to notice any. The differences, however, so far as regards the tibial spurs 

 are similar to those of Macrodactylus, though not quite the same. The anterior tibiae 

 have a single spur in both sexes, and the females two on the four hinder legs, but in the 

 males the hindmost tibise are destitute of spurs in most of the species, and armed with 

 a single, long spur in others, and the middle tibiee have two. Sexual differences exist 

 also on the fifth and sixth ventral segments. 



UU2 



