There’s nothing like the scientific thrill of discovering something for the very first time - or, in rare cases, rediscovering something that most people had presumed forever lost.
Echo maxima* was described in 1904 by the French entomologist René Martin based from one female collected by the German entomologist, insect trader and explorer Hans Frushstorfer. The holotype is deposited in the National Museum of Natural History, Paris, France. This female is the only specimen in museum collections and no additional observation in the field have been made since then. With a wingspan of ca. 120 mm and a body length up to 90 mm, Echo maxima is one of the largest Caloptera actually known in the world, equaled only by Archineura incarnata and A. hetaerinoides. According to Matti Hämäläinen, who have examined the holotype, this species more likely belongs to the genus Archineura*.
*Subsequently, in December 2015, Matti Hämäläinen published a paper in which
Echo maxima is transferred to the genus Archineura (paper here)
Holotype of Echo maxima (photo taken in 2007 at the National Museum of Natural History, Paris, France). After more than one century, this specimen is still in very good condition, as you can see !
Concerning the type locality, no other information than “Than-Moi, Tonkin” is given by Martin. This locality probably corresponds to Than Muội “village” (xã in Vietnamese), in Chi Lang (Chi Lăng) district, Lang Son (Lạng Sơn) Province (google map here), approximately 130km north of Hanoi.
At the time when Hans Frushstorfer collected this species (before 1904), Chi Lang and Huu Lung (Hữu Lũng) district were probably still covered by primary forest - mainly karst forest. However, over the past century, this area has lost almost all of its original vegetation through the spread of farming, mining, timber plantation. Actually, along the busy Nationale Road 1, which passes through these two districts, most of the hills are covered by industrial tree plantations (of exotic fast-growing trees). The nearest remaining good forest fragments are preserved in the Natural Reserve of Huu Liên (Huu Lung district), a few dozen kilometers west from the (supposed) type locality. Most of the recent efforts survey have been concentrated in this protected area. Without success, for instance...
It the IUCN Red List of Threatened Species, Echo maxima is classified as Critically Endangered (i.e. faces an extremely high risk of extinction in the wild).
Each year, numerous species thought to have disappeared are rediscovered. According to a recent study (The World's Rediscovered Species: Back from the Brink?, Scheffers BR & al., 2011), over the past 122 years, at least 351 amphibian, bird and mammal species have been rediscovered, most occurring in the tropics. These species, on average, were missing for 61 years before being rediscovered (range of 3–331 years). The number of rediscoveries per year increased over time and the majority of these rediscoveries represent first documentations since their original description.
Is Echo maxima still out there? As with so many species that are missing and presumed lost, hope remains eternal...
Nota : A part of this paper was translated from an article of Phan Quốc Toản in Vietnamese entitled “Hy vọng mong manh về loài chuồn chuồn cực kỳ quý hiếm” (here) published in 2012 on ThienNhien.Net.
Description of female Echo maxima by René Martin
(translated from French):
Black face with 2 yellow spots on the “superior lip” (labrum) and several yellow spots at “each sides of the lips” (mandibles?). “Nasus” (postclypeus) and upper surface of head metallic green, except 2 yellow spots on each sides of ocelli. Antennae black, “first joint” (scape) yellow.
Prothorax metallic green but black in the middle.
Thorax entirely metallic green, except a yellow line on each side reaching the wings.
Abdomen cylindrical, slender, metallic green but black from S5 to the tip, sides of S8-10 yellow. Caudal appendages black, small, slender, divergent.
Wings rather large, with yellow pterostigma covering 8-10 cells, marked as follows: ground colour brown from base to nodus between costal and median veins; rather large, light brown bands crossing vertically all wings, larger on hind wings. The area between the wing base and the band opaque shiny white-yellow, the one between the band and the wing tip not shiny (hyaline?) tinted with light yellow.
Fore wing : 36-37 antenodal cross veins and 39-40 postnodal cross veins.
Measurements (mm): Hind wing 50; abdomen 66.
Specimen caught in June or July.