THE TROPICAL AGRICULTURIST. 
[Feb i, 1895. 
It is also very desirable that repeated introductions | 
in every month of the year be made. It is known 
that they are breeding here, and we may well hops I 
that tbey will even now prove more than a match 
for their foes and triumph over them, and banis 
from our midst not only the black, but the frosted 
and soft brown scales. 
I wish to thank Mes-rs. Loop, 0 ^le, Phillips, Foote 
and Ritcliff for coirteous aid, and especially Mr. 
Pease for moit valuable and frequent assistance 
during the season. 
Immediately f 11 r.ving Prof. Cook's timely report 
Miss Jean L ;omis stud nt of Po.nona Col Ice, Care, 
mont, read an interesting p>per illustrated by enlarged 
drawings, on 
SCALE INS2CT. 
Mr. President, Ladies and Gentlemen: Five yeais 
a^o Ca'ifornia was excee ingly dKturbed over the 
ecale insect question, and she had good reison to b . 
A soft white scale, introduced into a few orchards 
011 imported nursery slook, had a'taiued such piopor- 
tions that it seemed likely tod stroy our whole fruit 
industry. 
The story of the rise and fall of the cottony cushion 
scale is ttill fresh in memory, and we love to recall 
it only in connection with the le sons it taught us, 
The ladybird Vedalia cardinal! 1 has many COU ins 
and allies as ready as she to befri -1 d us, it on y 
we seek them out, and Icerya pu cbasi has a leg on of 
confederates, as ugly as he, leady t> slip in tipou us, 
it a day off our guard. Eternal vigilance is the price 
of fruit production in Southern 1 alifornia. 
When every orchardist has made hiins If acquainted 
with Ue facts in the case and kno*s the habits of 
the different spec : es, then can we espect a complete 
riddance of the entire tribe. Oar scientists and 
inspectors visit our orchards only once or twice a 
year at d are liable even then to overlook an important 
insect- which, if not understood by the orchardist 
hims If, may before another visit reveal an alarming 
prevalence, as mauy in-cets have enormous powers 
of leproduction. 
With the aid of some instruction and the use of a 
compound microscope, I have lear ed a f. w things 
about the scale insects of our,, region that may be of 
interest, perhaps even new to some of you. 
Taking the subject tcientifically, the general term 
of the whole family of scale insects or bark lice is 
Coccidas. The most of the Coccids are injurious to 
man's welfare, but 1 ot all of them. Our eocnineal 
is but the dried bodies of a species living on the 
cactus plants in M. xico. ShelLc and Ciiiea wax are 
secretions cf Coccids. The three genera most abun- 
dant on oar coast are of no commercial value }et 
use ltrinel. The distinguishing feature of these thiee 
genera are easi y learned aad readily recognize *. 
The Lecania, in the adult state of the fern .le. are 
usually large, hardshelled, very convex scales. Trey 
are oval in shape and have a deep incision at the 
anal extremity: and are illustrated iu the Lecaniutn 
oleae, our common black > cale. 
The Aspidioti are small flat scales composed in part 
o! the moulted skins of the insect, and in part of a 
waxy secretion. Their form is circular with a tiny 
protuberance in the centre. The San Josd scale (A. 
perniciosusj is a fair example. 
The Mytilaspis is like the Aspidiotus in its com- 
position of moulted skins and insect secretions, but 
there need never be any confusion between the two, 
for they are very unlike in appearance. The 
Mytilaspis is a long irregularly shaped scale pointed 
at one end. We have one specimen here, M.. ci:ricola 
or purple scale. 
A minute and careful description of the habits of 
each species would be necessarily long and tedious 
A correct description would be impossible at this 
time, for no one has as j et given the subject a thorough 
study. In fact nearly all that we do know of them 
has been learned wi-hiu the last 15 or 20 ya:s. 
A general description should be prefaced with a 
mention of the dillerences m repri d ction a„d time 
of development of die insects. They are usually 
hatched fr 111 eggs deposited in varying numbers 
beneath the shell of the scale, tLe body of the . r emale 
shrinking in size to make room for them. There 
have been found from 1000 to 1800 eggs by actual 
count, beneath a single shell of the black nc*l«, Th se 
are one year developing to the adu't (-tale. Certain 
species of the Mytila-pis deposit egg* aiadually, a 
few each day, continuing for seveval weeks, au 1 these 
have four or five generations a jear. Other scales 
are believed to be viviparous. 
As <oon as hatched the young scale leaves the 
maternal roof and make his own livin . With (harp 
eyes or a small lens, he can l e seeu wander ng about 
on twig or leaf seeking a location. In a few hours 
he settles and, with a beak Death as long as his body 
inse ted iuto the leaf tissue or soft bark he withdraws 
the sap which belo-g- to the fruit. 
When he has grown too large for bis skin, he moults 
and continues feeding upon the sap of th - tr e. 
Until the tim=> of the secv d iconlt t l e male »nd 
fern ile are di tinguishahle only in size of the scale, 
the femal ■ being nearly four Units as large ae her 
brother. Put after the second moult the difference 
between the two is very pronounced. The It-male, 
now nearly or quite matured, attaches herself firmly 
to the branch by finelv spun threads or glue, com- 
pletes her scale covering, piodnces her young and 
dies while her lord undergoes a complete transforma- 
tion, and conies forth an airy-fairy little cr ature with 
a pair of win:s and two "long be ut ful antenna; 
He loses bh bea\ and in fact all m uth parts and 
receives iu their place another pair of eyes He sees 
thereafter and flies, but e U no more and lives but 
a short time. 
There are three common sp cies of the Lacanium 
The black scale (L. o'eas . our darkest spec es, is readily 
recognized by ti e leter II unon itsbaclc. It is a most 
annoying pest, infesting almost e*cry tree and nhrub 
in orchard and yarJ. The ex'-relion of the young 
scale, a sort of "sticky substance sometimes called 
"honey dew." upon which a black fungus forms, 
destroys ti e beauty of the tree and injures the sale 
of the fruit. Many experiments have been tried for 
the destruction of this scale, but without much success. 
The most c-ffe live remedy has been the hydrocyanic 
acid gas treatment, which has held this pest in check. 
But it has been found expeufive and from t' e nature 
of the case unable to reach all scale. We ure 1 ow 
awaiting results of the introduction of tl e b'ack 
Australian ladybird (Rhizobius veotra'is) said to be 
the natural enemy of the bUck scale, an inse t that 
has done most effective service at Santa Barbara. 
Unless the green lact -winged fly (Chrysop 1 < aliforoica) 
should prove a formidable enemy to her lady -hip we 
may conside- our trcubles with the black scale as past. 
Another Lecauium, the soft brown scale \JL. hts- 
peridum) is found only on citrus re s. It has the 
Lecaniutn markings excepting it is soft and nearly fla'. 
It is very prol tic and is sometimes so thick upon a 
branch that one overlaps another. Such a branch 
is usually -removed and b'.med, or should be. If given 
a fair chance, the soft brown scale would be a serious 
pest. It is believed that a small Chalcid fly parasite 
is keeping it in check. 
The frus:ed scale t,L. pruinosum) has be n recently 
observed to be increasing. It is a veiy large dark 
brown sca!e, shaped something like a bonnet. At 
certain seasons of the year it is di.sted over with a 
white powder, whence its common name. It infe ts 
nearly all the de iduous trees, seeming to prefer the 
prune. Its favorite location is just beneath a new 
shoot. If the black ladybird does all that is expected 
of her, she will feed upon thi-i Lecauium a 1 so. Other- 
wise we sh ill have to watch this f osted scale closely, 
and look for another remedy. 
Of the Aspidioti we have the San Jos6 scalo (A. 
pemicosus on our deciduous trees. Tnis is a small 
gray scale with yellow central tip, and is scattered 
thickly upon the bark of an infested tree. It s Ules 
also upon the fruit which it disfigures and renders 
unsalable. The San Jose scale was once a dr : aded 
pest, but is now known to yield readi' to the lime, 
salt and sulphur wash anl is no longer f jarc-d. More- 
over, it is a favorite dish for the little twice stabbe 1 
ladybird, Chilocorus bivulnerus. 
The Aspidiotus citrinus or yellow scale, infesting 
citrus trees only, is quite common in some sections. 
