1042 The American Naturalist. [Deeember, 
based on specimens from Mexico, presenting differences in 
color and the amount of cottony matter. 
In the same work (Essai sur les Cochenilles) Signoret gives 
. a definition of C. cacti which may be taken as fixing the strict 
application of the name. Properly, therefore, the insect is 
Coccus cacti L., sens. Sign., and its principal characters are as 
follows: 
Female. Dark red-brown, 6 to 7 mm. long, 4 wide, 2 to 3 
high, with a great quantity of whitecottony matter. Segmen- 
tation distinct. Back more or less keeled. Antenne short, 
conical, 7-jointed, the four basal joints short, wider than long ; 
joint 7 as long as the two before it together. Larva with 6- 
jointed antenne. 
Male. Red-yellow, legs and antenne brown. Antenne 
10-jointed, hairs on antenna knobbed. 
In Ashmead's Generic Synopsis of the Coccidee, the genus 
Coccus forms a tribe Coccini, distinguished from the tribe 
Acanthococcini by no very tangible characters. It is stated 
that the male is apparently without ocelli (see however, Sig- 
noret's figure) and the adult 9 lacks the bristles on the anal 
ring. Maskell (New Zealand Scale Insects) had earlier placed 
Coccus in a subdivision by itself, defined thus: *Adult females 
active, covered with mealy secretion ; antennse of seven joints; 
no hairs on anogenital ring. Eyes of male not facetted." 
The question as to there being two or more species, after 
being answered in the negative by Signoret, was again raised 
in 1884 by Lichtenstein. This entomologist had received 
specimens from Mexico which he considered to be the Coccus 
tomentosus Lam.; but he not only regarded this species as dis- 
tinet from cacti, but transferred it to Acanthococcus—a genus 
known hitherto only from Europe and New Zealand. 
The nomenclature of the Cochineal insects, according to the 
latest researches, is, therefore : 
Tribe COCCINI. Genus COCCUS L., Sign. 
Coccus cacti L., Sign. 
- Tribe ACANTHOCOCCINI. Genus ACANTHOCOCCUS Sign. 
ACANTHOCOCCUS TOMENTOSUS (Lam.) Licht. 
So " genus Coccus would still remain monotypic, were it 
