50 OKTHOPTEBA. 



A 2 . Hind wings with the dusky portion light, irregular, occupying less than 



two-thirds of the apical portion, often in great part composed of the 



infuscation of the veins. 



b 1 . Larger. Tegmina almost without mottling ; the infuscation of the 



wings little more than the darkening of the veins. [Pacific slope 



of Mexico northward.] 3. magna, sp. n. 



b 2 . Smaller. Usually with conspicuously mottled tegmina ; the infus- 

 cation more decided, but tessellated with hyaline in the female. 

 [Mountain regions of eastern slope of Mexico between 1000 and 

 6000 feet altitude.] 5. sumichrasti, Thom. 



1. Machaerocera mexicana, Sauss. 



Machaerocera mexicana, Sauss. Rev. et Mag. Zool. xi. p. 391 (1859) \ 



" Fuscous, with a pale longitudinal stripe. Pronotum granulose, rugulose, and carinated, the carinas inter- 

 rupted in the middle ; posterior margin angulate ; apex subemarginate ; the posterior area flat above, each 

 side carinated. The posterior femora marked with three yellow bands ; posterior tibiae blue, with a 

 testaceous ring at the base. Wings fuscous ; the base and posterior portion bluish. The subanal plate 

 of the male tricuspidate. 



" 6 . Length 1-2 in. $ . Length 1-8 in." 



Hah-. Mexico 1 , Tampico (Mns. Geneva), Temax in N. Yucatan (Gaumer). 



A specimen borrowed from the Museum in Geneva, Switzerland, is now before me ; 

 it is a male, labelled in Saussure's handwriting and undoubtedly typical. This insect, 

 which is from Tampico, measures just a trifle less than 30 millim.. from the anterior 

 point of the vertex to the tip of the closed tegmina, and agrees in every particular 

 with the above brief description. In the ' Biologia ' collection there are two others, 

 6 and $ , from Yucatan. 



2. Machaerocera obscura, sp. n. 



General colour very dark brown, the wings narrow, largely and heavily infuscated. The insect with a more 

 slender body and longer antennas than usual, and with a very prominent pale annulation near the base of 

 the hind tibiae, which are very dark but with a bluish tinge. Structure of vertex, face, and pronotum 

 much as in M. mexicana and M. sumichrasti. Although the general colour is very dark, there are 

 indications of the usual fine mottling on the tegmina and of lighter bands on the hind femora, the inner 

 face of the latter especially showing the bands conspicuously. 



Length of body, 6 19-20, $ 33 ; of antennae, <S 13, $ 13'5 ; of pronotum, tf 4, $ 7 ; of tegmina, <$ 21-22, 

 5 31-32 ; of hind femora, S 12, $ 18 millim. 



Hab. Mexico, Rio Papagaio [1 <s , 2 $ ], Tierra Colorada [1 <s ], and Rincon, all in 

 Guerrero (H. H. Smith) ; British Honduras, Rio Sarstoon [Blancaneaux : $ ) ; Guate- 

 mala, San Geronimo (Champion: s $ ). 



Whether the three forms referred to above are geographical races of a single species, 

 or distinct, matters but little. The only way to decide this would be to study their 

 habits in the field. 



