166 Mr. R. McLachlan on 
longitudinal median impressed line, without markings, but the sides 
often somewhat brownish; rest of the body, with the underside, 
ordinarily without markings, but the thoracic lobes sometimes 
suffused with brownish ; legs pale, tarsi somewhat obscure externally, 
claws testaceous, slightly, but gradually, dilated at the base, 7.e. 
“simple” as opposed to the common condition in which the claws 
are suddenly dilated. 
Wings rather broadly oval, obtuse, vitreous, iridescent ; neuration 
open, mostly whitish, but the nervules are black at each end, and 
are furnished with distinct minute black tubercles, whence spring 
short black hairs, causing a distinct punctate appearance under the 
lens ; pterostigmatic space long, greenish, with 3 or 4 somewhat 
thickened subcostal nervules beneath it ; dividing nervule of third 
cubital cellule extending only slightly beyond the superposed nervule, 
11—14 costal nervules in anterior wing, about 9 cellules between 
radius and sector, which latter is strongly angulate, gradate series 
parallel, 2—3 nervules in the inner and 3—4 in the outer (ordinarily 
2 in the inner and 3 in the outer in the posterior). 
Length of body 5°5—7 mm., expanse 16—21 mm. 
The foregoing description has been made from eight 
examples (which I regard as typical), taken by M. L. 
Bleuse at Ain Séfra in South Oran ; and I have recently 
seen others collected much further south in the Sahara by 
Dr. Chobaut. I have also a series of eight examples taken 
by Mr. Eaton at Biskra in May and June, 1893 and 1894; 
the species seems to be common there. All these latter 
have the head more or less strongly suffused with 
sanguineous, causing quite a peculiar appearance. I feel 
sure this is due to the action of ammonia in the killing- 
bottle, nevertheless it seems advisable not to consider the 
Biskra examples as typical. It is highly probable that a 
similar change of colour from the same cause has occurred 
in the types of some exotic species. 
C. cavifrons is clearly allied to C. genet and is about the 
same size, therefore one of the smallest species. 
Chrysopa nana, McLach, 
Trans. Ent. Soc. Lond. 1893, p. 231, September, 1893 
(=Ch. pretiosa, Gerst., Mitth. Verein f. Neuvorpommern 
und Riigen, xxv, p. 158, 1894).* 
Hab. Biskra, 3rd June, 18938, 1st May, 1894, 13th, 21st 
and 27th May, 1895. 
* The “ Mittheilungen ” (xxv) for 1893 are dated 1894 on the cover. 
