123 
the “ succhiatoio’’ and the clypeus (vid. Plate IIL., Fig. 2b). This proboscis 
is, as above remarked, held deeply fixed in the tissue of the plant upon which 
the Scale Insect occurs, and remains so during its entire stationary existence, 
its component hair-like organs together forming a tube through which the 
piant-sap is imbibed. This apparatus* that subserves the purpose of feeding, 
and which is constructed on one plan in almost all Coccide, has been 
described with some detail, since—as is obvious—it constitutes the means by 
which the scale insect establishes the injurious relationship to the plants that 
is often of such momentous significance to those whose interests are connected 
with their successful growth. 
Protected by its scale-covering, formed, as has been seen, partly of its 
discarded skins, but principally of a specially secreted portion, the insect 
“increases in size, and the latter pari passu with it. This scale itself presents 
differences of form or colour, according to the particular species of insect to 
which it belongs, being round, ovate, mussel-shaped, or elongate and parallel- 
sided. It may be depressed, or more or less elevated. Upon or in connection 
with it, occur the cast-off skins of the larva and nymph respectively, which 
often form a boss-like body, and maybe either central, excentric, or even terminal. 
Plate I., devoted to several different kinds of Armoured Scale Insects, illus- 
trates this statement. Already prior to its having obtained its fuli dimensions 
the union of the sexes may have taken place, and the body now becomes dis- 
tended with eggs (asshownin Fig. 7, Plate ITI.) or with larv, the latter each simply 
enclosed in a skin-like amniotic covering. It must, however, be borne in mind 
that in the case of the Diaspine (Armoured Scales) and Lecanide (Soft Scales), 
as in other sub-families of Coccide, the intervention of the male sex is by no 
means essential to the development and production of progeny, either in the 
oviparous or viviparous kinds.+ In fact, with some species it must be a 
most exceptional act, since the males are so extremely rare as to have been 
never met with. Dr. A. Berlese, who has paid special attention to the Scale 
Insects affecting the orange, writes regarding two of them—the Soft Scales, 
Lecanium hesperidum and L, oleae, figured on Plate II. (Higs. 2 and 4) —that 
he has never been fortunate enough to obtain adult males of either,t and his 
experience is that of nearly every other investigator. 
The act of parturition has been shown in the case of the San José or 
Pernicious Scale—Aspidiotus perniciosus—to extend on an average throughout 
a period of six weeks, and it has been estimated that from nine to ten young are 
born every twenty-four hours. At first—it is stated—the young are born 
with less frequency than subsequently happens, and that there is a correspond- 
ing reduction in reproductive activity towards the end of the life of the 
individual. In this insect, also, birth ensues by day or by night, perhaps more 
so during the day than during the night.§ From this it may be inferred that, 
rior to their extrusion, the development of the eggs, or of the young of the 
Reale Insect, is a gradual process.|| This gradual production of the young by 
the female, as remarked by the authors above referred to, has an important 
bearing on the question of remedies that aim at the destruction of the young 
as soon as they emerge from the female, since, in order to make them effective 
it becomes, consequent on this state of things, necessary to repeat them many 
times during a period of several (six in the case of Aspidiotus perniciosus) weeks. 
¥ 
* The writer’s information concerning this has been derived from A. Berlese, the learned 
Professor of the High School of Agriculture of Portici, whose patient investigations into the 
anatomy and morphology of certain Scale Insects, recorded in the different volumes of the Rivista 
di Patologia Vegetale, cannot be too highly extolled. sg 
+ The mode of union itself has been carefully described by Professor C. Sasaki in Bulletin, 
yol, ii., No. 3, College of Agr., Tokyo, Kombaba, 1896. 
t Rivista di Patologia Vegetale, vol. iii., p. 70, 1894. 
L. O. Howard, and C. L. Marlatt: The San José Seale. Bull. No. 3, New Series, Divis. of 
Entom. U. 8. Dep. of Agri., pg. 45. Washington, 1896. ? 
|| This would appear also to be the interpretation of the observations of Professor C, Sasaki 
regarding the metamorphosis of Diaspis patelliformis (?.D. amygdali, H. Tryon), recorded in his 
comprehensive article ‘‘On the Scale Insect of Mulberry Trees—Diaspis patelliformis, n.sp.” 
Bulletin, vol. ii., No. 3, pp. 112-118, Imperial University, College of Agriculture, Tokyo, 
Kombaba, 1894, : ; 
