6 HOMOPTERA 



who has sent the writer a considerable amount of interesting material from Peru, collected one species, 

 Gdastogonia rufomaculata Fallon, from the roots of water plants and from moss which was actually 

 under water in the mountain stream Utcubamba in San Ildefonsa, Peru. The insects were taken on 

 July 24, 1936. Mr. Woytkowski states (in correspondence) : « These were positively submerged in 

 water and the stream has a powerful current ». This is the only example known to the writer of 

 aquatic or semiaquatic Mtmbracida and we believe the case to be entirely accidental since the species 

 concerned has no physiological structures which would fit it for such a habitat. 



HABITS 



Field notes from all parts of the world indicate that the habits of the Membracida aie about the 

 same wherever they are found. Practically their entire life is spent on the stems and leaves of plants 

 where they feed, mate and oviposit and where the nymphs go through all of the instar stages. 



Their life is on the whole very quiet. The adults have the interesting habit of ranging them- 

 selves in rows on the branches, often thirty orforty individuals placing themselves so close together that 

 their bodies almost touch one another and remaining in this position for hours at a time. In the large 

 majority of cases the adult rests with its head poiiiting toward the base of the branch, or pointing 

 downward if it is on the trunk. By actual counts, made in many parts of the world, nine-tenths of the 

 individuals counted were found in this position so that it seems to be a universal habit but the reason 

 for it is entirely conjectural. It may be that such an attitude increases the resemblance of the insect (o 

 thorns, twigs or irregularities in the bark or leaf surface of the host plant, but this is not evident in ordi- 

 nary observation The nymphs are usually found tightly flattened in crevices of the bark or pressed 

 closely in the axil of a leaf or the crotch of a twig. In most cases the coloration of the nymph is such 

 that they are not easily seen when in such positions. This protective resemblance in many cases is 

 strengthened by the presence of the dorsal spines of the immature insect, which carry out leaf and 

 bark outlines to an extent which is very conducive to effective concealment. 



Membracids are generally most active during the warmest parts of the day. Feeding, mating, 

 oviposition and flight have all been observed oftenest during the hours from eleven o'clock in the mor- 

 ning until four in the afternoon, and more activity is shown on extremely warm days than on cool 

 ones. This may be due to the fact that the bird enemies or other diurnal foes of the insects are less 

 numerous during the heat of the day but such an explanation can be advanced only as a theory. In 

 the case of certain species attended by ants it has been suggested that the activity of the membracids 

 during the hours mentioned might be due to the activity of the ants at that time, but this may be the 

 converse of the true reason, since it may be that the ants are influenced by the membracids, and in 

 either case, there is no apparent reason why either insect should show increased activity at definite 

 periods unless it be because of tropisms of light or temperature. 



When at rest the insect generally chooses the underside of the first or second-year growth of the 

 trees or the uprightstem of herbaceous plants. The legs are spread rather widely apart, allowing the 

 abdomen to almost touch the host but keeping the hind legs in a suitable position for springing. This 

 position may be held for long periods of time, often for hours together, though actual records are not 

 avaiiable owing to the fact that the patience of the writer in timing the resting period of an individual 

 has never equaled the pleasure of the insect. Some species have the habit of moving spirally around 

 the twig, the movement being very slow but sufficient to accomplish a complete circuit of the twig in 

 an afternoon. It has been thought that this is done in an attempt to keep in the sunlight as the sun 

 moves across the sky, but this again is merely a conjecture. 



