vi 
Tlie Eiiro])enii scale insects used for dyes were replaced after the discovery of 
America by the cochineal insects: Coccus cacti, of Mexico. This insect feeds on 
a cactus called Nopal [Opunfia coccineUifcra) . Later this insect was intioduced 
into the Old World, and was established in a few places along the Mediterranean 
sea. In the Canary Islands it thrived so well on several species of cactus as to 
become an object of extensive commerce. The body tissues of these insects con- 
tained the colors from which the dyes were made. Aniline dyes have largely dis- 
placed coceid dyes. Axin, an external medicinal applicant, used also as a varnish, 
comes from the Mexican Coccid. Llaveia axinus. This seems to be a substance 
containing a peculiar acid, axinic acid. The so-called ground pearls are the 
encysted pupie of Coecids belonging to the genus Margarodes. These chitinous 
cysts, in the island of St. Vincent, are of sullieicnt size to be collected and strung 
for necklaces. 
Coccus (now Gossyparia) mannifera is a scale dwelling upon Tamarix in the 
Mediterranean basin. This scale exudes a honey-dew resembling honey. The 
Arabs use this honey-like substance for food, and call it “ Man.” It is supposed 
that this honey-dew or “ man ” is the real manna of the Israelites. 
Collection. The necessary materials for a collecting trip are: a staff witli 
crook handle, cigar-bo.x, package of envelopes, hand-lens, notebook, and strong 
sharp knife. The staff is used to draw down high overhanging limbs of trees. 
The cigar-box swung over the shoulder by a strap serves as a receptacle for en- 
velopes inclosing specimens. The hand-lens is for preliminary examination of 
the specimens. The notebook is to record data upon the specimens contained in 
consecutively numbered envelopes. The numbers in the notebook should of course 
correspond to the envelope containing specimens. 
The notes should include date of collection, food plant (and here great care 
should be e.xercised to secure accuracy; a handy pocket edition of Gray’s Field 
Botany is an almost indispensable companion), relative numbers present upon 
the host plant, and color of the scales. When the scales are on the trunk of the 
tree, the bark holding the in.seets can be removed. In case of twigs it will be 
more convenient to cut off the twig. When the laboratory is reached it will be 
found convenient to split out the center wood of the larger twigs. These twigs 
bearing specimens are ultimately to be ])laccd in cork-stoppered, flat-bottomed 
test tubes (cork-stoppered bottles will do). Adapt the length of the wood then 
to the length of the test tubes. The twigs, hark, or leaves bearing scales are now 
ready to be ])laced in small pasteboard bo.xes. An assortment of prescription 
boxes I find indispensable. Empty s])Ool-boxes will serve the purpose. The in- 
fested bark is to be left here until dry. If inclosed in the tubes before the sap 
is thoroughly dried out they will mould and materially damage the specimen 
thereon. While scales can be found in this latitude at any season of the year, 
the fall and early winter months are the best on account of the absence of leaves, 
and the presence of such forms as the adult Lccaniums, which die and fall off or 
are removed by sleets in the early spring months. Spring collecting should not 
be neglected, however, for this is the time when the males and nymphs can be 
most readily observed. At all times guard against the unnecessary removal of 
scales from their natural position on the cuticle of the host plant. The unskilled 
eye is sometimes deceived. Fungi and scars on the bark made by insects for the 
deposition of eggs, are mistaken for scale insects. Scale insects, not including 
gall, can be readily separated from the cuticle of the host plant without leaving 
an abrasion of the cuticle. 
Preparation for study. Under the various divisions, preparation of specimens 
