11 
not come within the scope of this treatise, as they are not insects, 
but because it usually falls to the lot of the economic entomologist 
to deal with them, and particularly on account of their novelty 
here in connection with pineapples, and their great economic im- 
portance, I have decided to include them in the discussion. Their 
real affinity, however, is with the true spiders, scorpions, ticks, et 
cetera. From insects they are distinguished by the possession of 
four pairs of legs (in the adult) and only two divisions to the 
body. Insects never have more than three pairs of legs, and the 
trunk of the body is always divided into three parts. 
The young of red spiders arise from eggs, which are laid, in 
the case of the pineapple red spider, on the surface of the leaf. 
The mouthparts are adapted for biting. The pineapple mite was 
first discovered in Florida, in 1899. It is known to have come 
here on plants from Florida on several occasions in recent years, 
when the plants were destroyed; probably the first to reach the 
Islands also came in this way. This furnishes an excellent exam- 
ple of the value of strict quarantine, and also shows the folly of 
introducing plants from abroad except under the most careful 
supervision to be exercised by those conversant with the risks so 
taken. The infestations which I have seen have been usually 
at the base of the leaves, where they are most completely imbri- 
cated and tightly clasped to the stem. The mites seem to flourish 
best in these situations, usually occurring in colonies in which 
are found all stages — eggs, larvae, and adults. While they are 
almost microscopic in size, they are readily discerned, or at 
least their presence is indicated by the reddish coloration given to 
the blanched tender tissue by their scarifying trophi. As in the 
case of the mealybug and scale, the most potent effect of their 
injuries is the entrance of spores of pathogenic organisms 
through the wounds which they inflict. They are very much pro- 
tected in the situations in which they are found from dusts and 
liquid applications, which would undoubtedly be effective if they 
could reach their object, and are known to be beneficial where 
the mites are so numerous that they have to spread to the more 
exposed surfaces of the leaves. Sulphur appears to be the most 
effective lethal agent, applied either as a fine dust or in combi- 
nation with lime as liquid lime-sulphur. It was supposed that 
however well mites might conceal themselves, they could be 
reached by confined poisonous gases, but this method, which 
appeared to be particularly well adapted to the treatment of 
slips, suckers and tops intended for planting, has proved unreli- 
able. Whether mites are peculiarly resistant to asphyxiation, or 
whether the gases fail to penetrate during their maximum con- 
centration, has not been determined, but so far the results of 
fumigation have been disappointing, as all individuals are not 
killed even when the concentration of the gas is pushed beyond 
the limit of safety to the plants. 
