Aug. z, 1921 
Red Date-Palm Scale: Technical Description 
671 
ing distribution map (fig. 1) by small black dots. Besides these, Wilsie 
( 14 ) and Popenoe (. 18 , p . 751) discuss this insect without giving definite 
distribution records. In every case on record, the host of the insect has 
been some variety of the date palm, Phoenix dactylifera L., and all of the 
evidence now available indicates that it is probably confined to this 
host in nature. 
The preceding definite records of the occurrence of this species indi¬ 
cate a very scattered distribution, but considering its habits and the meth¬ 
ods employed by human agencies in distributing its host, it is highly 
probable that this scale insect actually occurs wherever the date palm 
is cultivated, as has been suggested by Dr. W. T. Swingle and Prof. S. C. 
Mason, of the Bureau of Plant Industry, United States Department of 
Agriculture, both of whom have made collections of date palms for intro¬ 
duction into the United States; 
It is not possible at present to give definitely and accurately the rela¬ 
tionships of this species to other coccids. It has previously been placed 
as a member of the subfamily Dactylopiinae, which is obviously made 
up of a number of only slightly related groups, few of which have 
shaped themselves with any clearness thus far; and this species will, 
with little question, be found to be a member of some one of these in¬ 
completely defined groups within this subfamily. 
The recent study by Ferris (24) on the genotype of Sphaerococcus has 
shown clearly that the species under discussion has no close relationship 
whatever with Sphaerococcus, that Prof. Cockerell (r, p. 262; 2, p. 277) 
was entirely justified in erecting a new genus for it, and that the con¬ 
clusions of Newstead (10, p. 104 ) and of Lindinger (jjt, p . 247-248; 17, 
p. 689) to the effect that this species should be known as Sphaerococcus 
marlatti rather than Phoenicococcus marlatti are incorrect. 
The technical descriptions of the various stages of both sexes follow. 
Phoenicococcus marlatti Ckll. 
Larva (PI. 131, A-I).—Embryonic larva ready to emerge from female elongate 
oval, length about 0.27 mm., width about 0.13 mm.; antennae 6-segmented, placed 
rather close together at anterior apex of body, front of head between bases straight, 
basal antennal segment much enlarged, 12 microns long by 25 microns wide, stout 
truncate-conical, the remaining segments much more slender, approximately cylin¬ 
drical, the measurements of one antenna in microns as follows: II, 10.5; III 7; IV, 7 ; 
V, 7; VI, 18; legs small, the basal portion stout and the tarsus somewhat swollen, 
tarsal claw with denticle, the approximate measurements of a middle leg in microns 
as follows: Coxa, n; trochanter, 4; femur, 25; tibia, n; tarsus, n; claw, 7; digitule 
about 10.5; beak apparently i-segmented; with two pairs of thoracic spiracles, these 
small, each with a relatively long, flat, chitinized bar attached, and each with a single 
quinquelocular pore just anterior to the opening; derm with seven pairs of long tubular 
ducts, each terminating in a bilocular 8-shaped pore at its inner end, opening along 
the body margin, these two pairs on the head, one pair 011 the inesothorax, one on the 
metathorax, and one pair each on the first, fourth, and terminal abdominal segments; 
dorsally with three pairs of similar, but smaller ducts, one on each side about half way 
