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Rearhorses, or Praying Mantids

(Family Mantidae.)

The insects of this family formed the old Orthopterous group, known as Raptoria, or graspers. They are predatory insects, and are characterized by having a long, slender, prothorax, with the first pair of legs fitted for grasping their prey. They are like the Phasmidae, much more abundant in tropical regions than elsewhere, and, while many forms, by their shape and color, exhibit striking instances of protective resemblance, in others are seen in its highest development the phenomenon of aggressive resemblance. The so-called flower mantids in tropical countries closely resemble the flowers of certain plants, especially brilliant orchids, and in these flowers they lurk awaiting the visits of insects, which they capture. They have various popular names, being known in England as "sooth-sayers," or "praying insects," from the attitude which they assume when at rest or when waiting to grasp another insect. The knees are bent, and the front legs are held as though supporting a prayer-book. In our Southern States they are known as "mule-killers," from the curious superstition that the brownish liquor which they exude from the mouth is fatal to mules. They are more commonly known, however, in the south, as "rearhorses," from the rearing attitude assumed when about to grasp another insect. The eggs of the Mantidae are laid in a curiously-formed egg case which is secreted by the female. They capture their prey by stealth, crawling upon them so slowly that the motion is hardly observable, but when within reaching distance the front legs are thrown out with incredible rapidity. They are cannibalistic in a high degree, and the female often, if not usually, devours the male while in the act of conjugation.

Like so many other predatory insects, they have the most voracious appetites. Colic and bilious headaches seem unknown to them. Slingerland has brought together some interesting instances of this voracity in his account of the recent accidental introduction and establishment of the European Mantis religiosa in New York State. His correspondent, Mr. Atwood, writes: "One Sunday a green mantis ate three grasshoppers, each seven-eighths of an inch long, a daddy-long-legs, and then tackled another mantis, and I was obliged to interfere between them." It is probable that this common European insect was introduced into northern New York in the egg stage on nursery stock. Another foreign mantid has also recently become acclimatized in this country. This is Tenodera sinensis Sauss., of Japan. This large and striking form made its appearance about Philadelphia in 1896, and in 1900 was quite numerous.

Life History of a Rearhorse

(Stagmomantis carolina.)

This species, which is common throughout the southern United States, extends as far north as New Jersey. It is an austral form, but does not reach the northern limits of the so-called upper austral life zone. The eggs are laid in tough cases about an inch long which are attached to the twigs of trees. The case is tough and horny, and the eggs are laid in parallel rows, perhaps forty in a row, issuing from a common longitudinal middle line. All of the eggs stand on end and are inclined somewhat toward the central channel. A cluster of eggs has a braided appearance, but consists simply of a continuous ribbon of mucous folded in close fluting and having an egg deposited in the bight or angle of each fold. The eggs are deposited simultaneously with the deposition of this ribbon by the mother insect, and the whole mass is at first soft and flexible, but rapidly hardens by exposure to the air. The newly-hatched insect is light yellowish-brown, but after the second molt many of them become green. The number of molts has not been recorded, but there are certainly more than three. At full growth, however, most of the females are green, while the males become brown or gray. There is but one generation each year. The young hatch in the early summer, but complete their growth in the latter part of the season, and the insect hibernates in the egg stage. The eggs are frequently parasitized by a very peculiar chalcis fly, Podagrion mantis, which penetrates the tough egg mass with its long ovipositor, and whose larvae feed upon the eggs. Thus egg masses taken by the observer in the winter and kept for the hatching of the young will frequently in the spring give out these parasites instead of the young mantids.