1881 . ] 
223 
HOMOPTEEA. 
Fam. MEMBR A CIDM. 
Trtquetra intermedia, n. sp. ? 
Triquetra inermis , Fairm., var. ? 
Closely allied to T. inermis, but differs by tlie anterior dorsal ridge of the pro- 
notum being produced into a distinct, compressed, erect, and somewhat anteriorly- 
directed spine-like process. Length, 14 min. 
Hab. : Bogota (Dr. TJiieme). Coll.: Oberthiir and Distant. 
This form is intermediate between T. inermis , Fairm., and T. 
nigro-carinata , Fairm., and only differs by tbe following characters : 
— from the first, in which the dorsal spine is absent or obtusely 
indicated ; and, from the second, in which the same spine is much 
more produced. 
As in T. inermis , many specimens exhibit a strong tendency to 
develop prominently this pronotal spine, I should incline to the 
opinion that T. intermedia is only an intermediate form between the 
two other described species (?), and that the three are only phases of one 
protean type. Flowever, I have been reluctantly obliged to give the 
specimens described a specific name to prevent my treating T. inermis 
and T. nigro-carinata as synonymic, more especially as Stal has 
described another species, T. recurva , in which this spine is even more 
produced, but of which that author remarks : “ T. inermi et T. nigro- 
carinatce valde affinis, cornu dorsali ejusque forma divergens and 
also, “ In exemplo feminino, specifice baud diverso, cornu lateralia 
thoracis valde antrorsum et sursum vergunt.” This last observation 
may be probably explained by the law frequently enunciated and 
lately again exemplified in butterflies by Mr. Wood-Mason (J. A. S. 
B., vol. xlix, p. 418), that secondary sexual characters acquired by the 
male have been partially transmitted to some females, but not to others. 
As T. inermis , T. intermedia , T. nigro-carinata , and T. recurva , have all 
been received from Colombia, and as they are also distinct from other 
species of the genus in the common character, “Carina dorsali thoracis 
nigra,” and their specific differentiation depends on the amount of 
development of the anterior portion of the pronotal dorsal ridge, the 
probability of them all being but different forms of one protean species 
is much increased, and we may possibly only require larger series of 
specimens to find all the intermediate links. The words of Mr. Darwin 
may be here well applied : “ A part developed in any species in an 
extraordinary degree or manner in comparison with the same part in 
allied species, tends to be highly variable.” 
Selston Yillas, Derwent Grove, East Dulwich : 
January, 1881. 
